Testing of electrical installations is carried out to verify the compliance of the equipment with the necessary technical requirements.
In addition, during the tests, the absence of defects is checked, malfunctions and breakdowns are identified, and initial data is collected for further maintenance.
Our company offers testing of electrical installations in Moscow at a bargain price.
The work uses modern equipment and diagnostic systems, our employees have extensive experience in this field.
Types of testing of electrical installations
Testing of electrical installations and electrical equipment is divided into the following types:
- type testing;
- control tests;
- operational checks;
- acceptance checks;
- special testing.
Typical types of testing are carried out according to the regulations established by the equipment manufacturer. The frequency depends on the features of the installation, the requirements for its operation.
Control tests are carried out when the equipment is released from the manufacturing plant to confirm the specified technical and other characteristics.
Acceptance works are carried out after the installation of electrical installations, such works include testing at maximum loads, safety checks.
The rules for checking electrical equipment and electrical installations largely depend on the type of equipment itself. In our work, we are guided not only by existing standards, but also by the recommendations of manufacturers.
Prices for testing electrical installations
| Name of works | Unit | Unit cost works (rub) |
| Measurement of the resistance to the spreading of the earthing current | measurement | 300 r. |
| Measurement of current spreading resistance of a loop with a diagonal of up to 20 m | measurement | 364 r. |
| Checking the presence of a circuit between grounding conductors and grounded elements | dot | 29 p. |
| Determination of soil resistivity | measurement | 728 rubles |
| Measuring the impedance of the phase-zero circuit | pantograph | 110 r. |
| Measurement of insulation resistance of cable and other lines, 1-phase line | line | 92 p. |
| Measurement of insulation resistance of cable and other lines, 3-phase line | line | 100 r. |
| Checking circuit breakers up to 1000V, 1-phase | machine | 64 p. |
| Checking circuit breakers up to 1000V, 3-phase | machine | 109 p. |
| Measurement of insulation resistance with a megohmmeter of windings of machines and apparatus | measurement | 127 r. |
| Checking and testing of circuit breakers controlled by differential current (RCD), 1-phase | device | 126 p. |
| Inspection and testing of circuit breakers controlled by differential current (RCD), 3-phase | device | 146 p. |
| Checking the secondary switching | chain | 536 r. |
| Testing current instrument transformers | transformer | 1920 |
| Meter test, 3-phase | counter | 2960 r. |
| scheme | 280 r. | |
| Drawing up basic single-line diagrams | scheme | Negotiated |
| Drawing up a technical report | report | from 500.00 to 1000.00 rubles |
| The cost of tests and measurements in electrical installations over 1000V (up to 10kV) | ||
| A complex of operational tests and electrical measurements of power two-winding oil transformers with a power of up to 630 kVA. | transformer | 10000 r. |
| Testing of busbars and connecting bars | set | 5400 r. |
| Load Break Switch Test | switch | 2050 r. |
| Disconnector test | disconnector | 1700 r. |
| Checking the compliance of electrical installations with regulatory and design documentation | scheme | 280 r. |
Frequency of tests and list of works
The frequency of testing electrical installations is regulated by PTEEP:
- stationary electric stoves are checked once a year;
- elevators, cranes and other lifting devices with electric motors are checked at least once a year;
- lighting networks - 1-3 times a year (depending on the complexity of the systems);
- grounding devices - 1-3 times a year;
- resistance testing for electrical networks - every 5 years.
The cost of testing electrical equipment in Moscow depends on the type and complexity of the work, you can clarify the prices by contacting us at the indicated numbers.
Benefits of working with us
You can order testing of any electrical systems from us. All work is carried out by qualified craftsmen using high-quality equipment and the latest diagnostic techniques. Based on the results of the checks, an appropriate conclusion is issued indicating all the characteristics of the device under test. We offer our customers the following benefits:
- efficiency, exact observance of terms;
- quality assurance;
- use of modern equipment;
- favorable price for checking electrical equipment in Moscow;
- efficiency.
Our company tests and checks of electrical installations of various types, carried out in full compliance with current regulations. Our specialists carry out a full range of works, after which a conclusion is issued. To know detailed information You can call the indicated phone numbers or contact our office.
Tests of existing electrical installations of all consumers, regardless of their departmental affiliation with a rated voltage of up to 220 kV, must be carried out to the extent and at the frequency specified in Appendix E1 of the PTE. When testing electrical installations with a rated voltage of more than 220 kV, one should be guided by the current Testing Standards for electrical equipment of the Ministry of Energy and the instructions of manufacturers.
Specific testing periods for electrical installations are determined by the person responsible for electrical facilities on the basis of standards and a departmental or local system of preventive maintenance (PPR) in accordance with standard and factory instructions, depending on local conditions and the condition of the installations.
For certain types electrical installations not included in the standards, specific terms and test standards should be established by the person responsible for the electrical economy, based on the instructions of the manufacturers and the departmental or local PPR system.
Electrical equipment manufactured by foreign companies is subject to testing according to PTE standards after the expiration of the warranty period. Insulation of electrical equipment manufactured by foreign companies, which, according to the technical documentation, is tested with a voltage lower than that provided for by the standards, must be tested with a voltage set in each individual case, taking into account operating experience, but not lower than 90% of the test voltage accepted by the company, if there are no other instructions from the supplier.
The conclusion on the suitability of electrical equipment for operation is given not only on the basis of a comparison of test results with the Norms, but also on the basis of the totality of the results of all tests and inspections.
The values of the parameters obtained during the tests must be compared with the initial ones, with the results of measurements of the parameters of the same type of electrical equipment or electrical equipment of other phases, as well as with the results of previous tests.
The initial values of the measured parameters should be understood as the values indicated in the passports and factory test reports. In the absence of such values, the values of the parameters obtained during acceptance tests or tests after the completion of the refurbishment can be taken as initial values. If these values are also missing, it is allowed to take the values obtained during an earlier test as initial ones.
Electrical equipment and insulators with a rated voltage exceeding the rated voltage of the electrical installation in which they are operated can be tested with increased voltage in accordance with the standards established for the insulation class of this installation.
In the absence of the necessary AC test equipment, it is allowed to test electrical equipment of switchgears with voltage up to 20 kV with increased rectified voltage, which should be equal to one and a half times the value of the industrial frequency test voltage.
In the norms (Appendix E1 PTE) the following are accepted conventions types of tests:
K - tests during the overhaul of electrical equipment;
T - tests during the current repair of electrical equipment;
M - inter-repair tests, i.e. preventive tests not related to the withdrawal of electrical equipment for repair.
Assessment of the state of isolation of standby electrical equipment, as well as parts and parts of electrical equipment that are in emergency reserve, is carried out according to the standards adopted by the manufacturer for manufactured products.
Tests of electrical equipment must be carried out according to the programs (methods) set forth in the standards and specifications for testing and electrical measurements, in compliance with the requirements of safety regulations.
The test results must be recorded in the protocols that are stored together with the passports of the electrical equipment.
Electrical tests of insulation of electrical equipment and sampling of transformer oil from tanks of apparatus for chemical analysis should, as a rule, be carried out at an insulation temperature of at least 5 ° C, except for cases specifically stipulated in the standards when a higher temperature is required.
Before testing electrical equipment (with the exception of rotating machines and cases specially stipulated in the standards), the outer surface of its insulation must be cleaned of dust and dirt, except when testing is carried out by a method that does not require disconnecting electrical equipment.
When testing the insulation of windings of rotating machines, transformers and reactors with increased voltage of industrial frequency, each electrically independent circuit or parallel branch must be tested in turn (in the latter case, with complete insulation between the branches); in this case, one pole of the test device is connected to the output of the winding under test, and the other - to the grounded case of the electrical equipment under test, with which all other windings are electrically connected for the entire time of testing this winding.
Windings that are tightly connected to each other and do not have the output of the ends of each phase or branch should be tested relative to the body without disconnecting them.
When testing electrical equipment with increased voltage of industrial frequency, it is recommended to supply line voltage to the test setup.
The rate of voltage rise to 1/3 of the test value can be arbitrary. Further, the test voltage should rise smoothly, at such a speed that a visual reading on the measuring instruments is possible, and upon reaching the set value, it is maintained unchanged throughout the entire test period. After the required exposure, the voltage gradually decreases to 1/3 of the test voltage and turns off.
Under test duration means the time of application of the full test voltage specified in the Code.
Before and after testing the insulation with increased power frequency voltage or rectified voltage, it is recommended to measure the insulation resistance using megaohmmeter. The one-minute value of the measured resistance is taken as the insulation resistance R 60 .
The results of the overvoltage test are considered satisfactory if, when applying the full test voltage, no sliding discharges, leakage current surges or steady-state rises, interruptions or flashovers were observed, and if the insulation resistance measured by a megohmmeter remained the same after the test.
When measuring the insulation parameters of electrical equipment, random and systematic errors should be taken into account due to errors in measuring instruments and apparatus, additional capacitances and inductive couplings between the elements of the measuring circuit, the effect of temperature, the influence of external electromagnetic and electrostatic fields on the measuring device, method errors, etc.
When measuring the leakage current (conduction current), if necessary, the ripple of the rectified voltage is taken into account.
The standards for the dielectric loss tangent tgδ of electrical equipment insulation and for the conduction current of arresters are given for measurements performed at an equipment temperature of 20 0 C. The dielectric loss tangent of the main insulation is measured at a voltage of 10 kV for electrical equipment and bushings for a rated voltage of 10 kV and above and voltage equal to the nominal voltage for the rest of the electrical equipment.
The dielectric loss tangent of the insulation when drying the transformer without oil should be measured at a voltage not exceeding 220 kV. When measuring the tangent of the dielectric loss angle of the insulation of electrical equipment, its capacitance should be simultaneously determined.
A test with a voltage of 1 kV of industrial frequency can be replaced by measuring a one-minute value of insulation resistance with a megohmmeter for a voltage of 2500 V. This replacement is not allowed when testing critical rotating machines and relay protection circuits, and electric automation, as well as in cases specified in the relevant sections of the standards.
When comparing measurement results, take into account the temperature at which the measurements were made and make corrections in accordance with special instructions.
When testing the external insulation of electrical equipment with increased voltage of industrial frequency, carried out under environmental factors that differ from normal (air temperature 20 ° C, absolute humidity 11 g / m 3, atmospheric pressure 101.3 kPa, if other limits are not accepted in the standards for electrical equipment ), the value of the test voltage should be determined taking into account the correction factor for the test conditions, regulated by the relevant standards.
When carrying out several types of insulation tests on electrical equipment, a test with increased voltage should be preceded by a thorough inspection and assessment of its condition by other methods. Electrical equipment rejected during external inspection, regardless of the test results, must be replaced or repaired.
The experience of no-load power transformers is carried out at the beginning of all tests and measurements before supplying the DC transformer windings, i.e., before measuring the insulation resistance and DC winding resistance, heating the transformer with DC, etc.
The insulation temperature of electrical equipment is determined as follows:
– the temperature of the upper layers of oil, measured with a thermometer, is taken as the insulation temperature of a power transformer that has not been heated;
- the average phase temperature is taken as the insulation temperature of a power transformer that has been heated or exposed to solar radiation IN windings of higher voltage, determined by its resistance to direct current;
- for the temperature of the insulation of electrical machines that are in a practically cold state, the ambient temperature is taken.
- for the temperature of the insulation of electrical machines subjected to heating, the average temperature of the winding, determined by its resistance to direct current, is taken;
- the temperature of the insulation of the bushing installed on the oil circuit breaker or power transformer, not subjected to heating, is taken to be the ambient temperature or the temperature of the oil in the tank of the circuit breaker or power transformer.
The terms and norms of preventive measurements and tests are given in Table 6.
Table 6 - Terms and norms of preventive tests
|
Type of wiring and electrical equipment |
Measurement instructions (megger voltage, frequency and other instructions) |
Resistance rate MOhm |
|
Power and lighting wiring; distribution devices, shields; electrical devices 0.38–0.66 kV Power cable lines up to 1 kV Transformers up to 35 kV Electric motors up to 0.66 kV (stator winding) Hand tools and portable lights |
1000 V. in dry rooms at least 1 time in 6 years. In particularly damp and hot rooms, in outdoor installations, as well as in rooms with a chemically active environment at least once a year. They are measured between any wire and ground, as well as between any two wires with the fuses removed and the power receivers turned off. 2500 V. In stationary installations at least 1 time in 5 years, and seasonal - before the onset of the season. 2500 V. Frequency - according to local regulations. 1000 V. Periodicity - according to the PPREsh system, but for engines of critical mechanisms and those operating in difficult conditions at least 1 time in 2 years. 500 V. Periodicity - according to the PPREsh system, but at least 1 time in 6 years. |
not standardized, but not lower than 70% of the previous measurement 1.0 - in a cold state; 0.5 at 60°C |
For asynchronous motors, the operation of the maximum protection is checked by measuring the impedance of the phase-zero loop, followed by determining the single-phase short-circuit current.
In electrode water heaters (boilers), the specific resistance of water is measured and it is ensured that it is within 10–50 Ohm m at 20 ° C. The operation of the boiler's protective equipment is checked.
For overhead lines, check the overall dimensions, insulators, junctions of wires, the degree of decay of parts of wooden supports and the operation of line protection. The scope and timing of the tests are regulated by local regulations.
Preventive measurements of the resistance of grounding devices are carried out within the time limits established by the PPREsh, but at least once every three years. To obtain reliable results, measurements are recommended to be carried out during periods of greatest soil resistivity. The resistance of repeated ground electrodes should be no more than 30 Ohm m at the specific soil resistance 100 Ohm m (no more than 0.3 at > 100 Ohm m), and the neutrals of transformers and generators - no more than 4 Ohm at 100 Ohm m (no more than 0.04 at > 100 Ohm··m). Grounding conductors of electric boiler rooms must have a resistance of not more than 4 ohms.
Electrical potential equalization devices are checked annually for touch and step voltage or for the integrity of conductors available for inspection.
OPERATION and repair of EQUIPMENT (5 course)
LECTURE №12
Diagnosis and testing of electrical equipment
Study questions:
- Diagnostics of electrical equipment during maintenance and repair.
- Purpose and types of testing of electrical equipment.
3. Optimal detection and search for failures.
1. Diagnosis of electrical equipment during maintenance and repair
Determination of malfunctions and causes of failures of simple electrical equipment, electrical personnel does not cause much difficulty. This is also facilitated by operations carried out during scheduled maintenance.
To identify the causes of malfunctions in complex electrical equipment and complex electrical circuits, it is recommended to draw up search algorithms that indicate the most rational sequence of operations. This sequence ensures the minimum time and cost for troubleshooting.
The most common troubleshooting methods are:
Consistent functional analysis;
half split;
Probabilistic-temporal method.
Sequential functional analysis methodis based on the definition of the main functions of the controlled electrical equipment or circuit. By checking the functional parameters, deviations are found and the failed element is installed.
This method is quite simple, clear, but the troubleshooting sequence is not optimal.
For electrical equipment with a series connection of elements, it is often usedhalf split method.According to this method, an element is first determined that divides the control object into approximately 2 parts, the probability of failure of which is approximately the same. Then, in the faulty half of the object, an element is again found that divides this half into parts that have the same probability of failure. Such operations are carried out until a failure is detected.
Probabilistic-temporal troubleshootingusually used for complex objects and circuits. The informative basis of this method is data on the probability of failures or the probability of failure-free operation of elements or the probability of failure-free operation of elements and the time spent on checking them. To conduct a search on the structural or electrical diagram of electrical equipment, a functional model is built, and then a fault matrix is compiled. This matrix usually has next view:
The upper part of the matrix contains a list of all the main signs of malfunctions;
In the lines - a list of causes of failures or failed elements, a change in the state of which can cause symptoms of malfunctions.
Troubleshooting begins with checking the item that has the smallest ratio of test time to failure probability and duration until the failed item is found. The program constructed in this way ensures the minimum time spent on troubleshooting.
2. PURPOSE AND TYPES OF TESTSelectrical equipment
Tests of electrical equipment serve as the basis for ensuring the required quality in its manufacture and repair. Only they allow to make an objective conclusion about the compliance of the parameters and characteristics of electrical equipment with the established requirements.
The scope and standards of testing are regulated by multiple domestic and international documents (there are about 50 of them).
According to their purpose, they are divided into three troupes:
Typical and control;
Acceptance;
Preventive and other operational tests.
Type and control testselectrical equipment is carried out at the factory according to the program and methodology set forth in the relevant standards. If it is not possible to carry out any tests at the factory, they are carried out at the place of installation of this electrical equipment.
Type testsare carried out in order to determine the suitability of a serial batch of electrical equipment and verify compliance with the requirements set for it by the standards, and in the absence of them, by the technical specifications for delivery. The timing of type tests and the number of electrical equipment to be tested are also established by standards or specifications.Control testselectrical equipment is carried out in order to check the quality and compliance of its characteristics with the calculated data.
acceptance testsall newly installed and reconstructed electrical equipment as a whole must be subjected to on-site. The purpose of these tests:
Examination technical condition electrical equipment, instruments and apparatus, primary and secondary switching and the quality of their installation;
Identification of compliance of electrical equipment with the project and requirements of GOST;
Taking characteristics and comparing them with the results of factory tests;
Adjustment, adjustment and inclusion in the work of the entire technological installation as a whole.
During commissioning and acceptance tests, significant shortcomings of the design and installation of equipment can be identified and proposed rational decisions for their elimination. This is an important aspect of the work of an electrical equipment adjuster. In addition, these tests should serve as the initial data for comparing with them the results of preventive tests carried out under operating conditions during the overhaul period and during routine inspections. According to the PUE, a conclusion on the suitability of putting the equipment into operation is made on the basis of an analysis of the results of acceptance tests for the electrical installation as a whole. Evaluation of non-standardized values is carried out by comparing the values obtained during the test with the test results of the same type of equipment, as well as with the available results of factory or previous tests.
Equipment with satisfactory test results is put into operation after it has been tested in the operating mode. So, for example, it is allowed to put into temporary operation turbogenerators and other main and auxiliary equipment of power plants, if, after continuous 72-hour operation, no shortcomings are found that impede their normal operation. Transformer points and power lines with voltage up to 10 kV inclusive are allowed to be put into operation by switching on by a push. It is known that commissioning and acceptance tests are carried out both during the installation of power plants, and after its completion before being put into operation.
Preventive testingelectrical equipment is carried out in operating conditions, they are very effective in terms of identifying defects, preventing emergency shutdowns of power equipment and downtime industrial enterprises. The widespread introduction of preventive tests also makes it possible to carry out major and other repairs of electrical equipment less frequently and ensures required quality supplied electricity (maintaining the normal frequency and the specified voltage level in the network).
Preventive tests are mandatory for the operation of all electrical installations. They allow you to detect malfunctions that cannot be established by inspection, because sometimes they do not have external manifestations. Timely elimination of such malfunctions prevents the occurrence of accidents and damage to equipment between repairs.
The scope of preventive testing of electrical equipment includes the following operations:
1) The insulation resistance of power wiring and electric lighting wiring is measured once every 2 years in rooms with a normal environment and once a year in other rooms. Resistance should not be less than 0.5 MΩ (1000 V megger).
2) Testing the insulation of wiring with increased voltage (1000 V industrial frequency) for 1 minute 1 time in three years. For this purpose, you can use a megohmmeter with a voltage of 2500 V.
3) When putting electrical equipment into operation after its overhaul and rearrangement, it is necessary to check the phasing and integrity of electrical circuits.
4) The insulation resistance of electric motors, devices and secondary switching circuits is measured within the time limits established by the person responsible for the electrical industry. For motors up to 500V, a 1000V megger must be used.
5) Elements of grounding devices located in the ground are inspected with the opening of the soil selectively at least 1 time per year. The circuit between grounding and grounding elements is checked at least once a year.
6) The resistance of blow-by fuses is checked during commissioning, repair of electrical equipment, and if it is suspected that the fuses have blown.
7) The resistance of the "phase-zero" loop in installations up to 1000 V with a solidly grounded neutral is checked during commissioning and then at least 1 time in 5 years. The resistance must be such that the single-phase short-circuit current exceeds at least three times the rated current of the nearest fuse-link and 1.2 times the tripping current of the maximum release of the corresponding circuit breaker.
Depending on the performers, qualification, attestation, operational, special and research trials.
Qualification teststhese are tests carried out by a special commission on selected samples of the pilot series or the first industrial batch in order to check the readiness of the enterprise to produce products of this type in a given volume.
Qualification teststhese are tests carried out to assess the level of product quality during its certification. Such tests are entrusted to specially appointed commissions, whose members take part in the tests together with the permanent staff of the testing station.
Performance testscarry out during the operation of large electrical equipment, their purpose is to check the health of the machine; test programs are set by the user.
In addition to these types of normal industrial tests, special and research tests can also be carried out.
Special testscarried out in addition to acceptance or acceptance tests according to special programs; their purpose is to establish the compliance of electrical equipment with special requirements determined by the standards or technical specifications for electrical equipment of this type and going beyond the requirements of general standards.
Research testscarried out over electrical equipment or a group of electrical equipment of a given type, a given series or a given type according to a program developed for each individual case.The purposes of these tests are very different; the most characteristic of them:
Obtaining initial data for the design of new types of electrical equipment or technical improvement of the existing one;
Establishing the possibility of saving the materials used and replacing them with other materials;
Checking the impact of new technological processes used in the manufacture of electrical equipment, on their quality;
Development of new calculation methods and refinement of existing ones;
Research of new schemes and combinations of electrical equipment both with each other and with other mechanisms, etc.
Special and research tests may largely consist of the same tests that are included in the acceptance test programs; however, they often include special experiences that go beyond these programs.
In the process of repairing electrical equipment, a series of tests are carried out, the purpose of which is to check the quality of the repair operations performed. For example, after winding the stator or rotor winding of an electrical machine, they check the absence of breaks and turns in it. Tests also check the quality of conductor connections by soldering or welding. Repaired transformers and electrical machines are tested according to a specific program, which includes identifying defects in repaired electrical equipment and checking their characteristics for compliance with standards and specifications.
3. Optimal detection and search for failures
The system is considered as an object of control (OC), consisting of a set of "n" elements (set W), interconnected by functional links. Each of the elements can be in one of two possible states: operability or failure. The probability of the working state of the i-th element is pi, and the probability of failure is qi, where qi=1-pi. It is assumed that the failures of individual elements of the system are mutually independent.
To control the performance and search for places of failures of the OK, it is possible to use tests ti, where i=1,...,m, allowing you to check "m" parameters, the nominal value of each of which is provided by the performance of the elements of a certain subset Wi. The test results can be classified as passing or failing.
It is more convenient to represent the set of tests as a matrix Т=||tji||, where i=1,...,m; j=1,...n, the rows of which correspond to the available tests, and the columns correspond to the elements of the set W. Thus:
I=1,...,m; j=1,...n.
The column vector С=(С1,...,Сm) determines the costs associated with the application of each test.
Control processes can be classified according to a number of criteria.
1) According to the depth of failure localization, the processes of monitoring the operability of the system as a whole and diagnosing are distinguished in order to determine the state of each element.
2) According to the method of carrying out, the control process can be divided into sequential and combinational. In the first case, the choice of each next test or the end of the procedure is made in accordance with some conditional program based on the results of previous checks. In the second case true state OK is determined after applying the entire set of pre-selected tests.
3) The sequence of the control procedure is usually evaluated by two types of optimality criteria: the minimum of average costs for the implementation of the program and the minimum of the maximum value of this value. The criterion for the optimality of a combinational search is usually the total cost of its implementation.
4) In the a priori determination of the set of admissible states, the OC accepts 2 hypotheses: in the OC, no more than one element can fail; Arbitrary combinations of simultaneously failed elements are possible.
5) Based on the totality of elements that remained unverified after the control, control is distinguished by complete or incomplete coverage of the QA elements.
3.1. Health monitoring and diagnostics of systems with a single failure
Formulation of the problem.It is known about the existence of one failure, the matrix of tests "T" and the probability of failures of each element are given - qi, i=1,...,n. It is necessary to select a certain group of tests sufficient to find the failed element and determine the conditional order of sequential application of the tests of this group (program) so that the average values of the total cost of the search procedure is minimal.
An Approximate Algorithm for Arbitrary Intersecting Tests. Suppose that by the beginning of the M-th step of verification, a sequence of tests has been carried out: d(M-1)=(t1,...t(M-1)) and the task is reduced to finding a failed element in the subset W(M-1).
The algorithm for finding a single failed element is as follows:
1. The values qj(0) are determined - the conditional probabilities of failure of the j-th element, if there is exactly one failed element in the checked set:
Note - then it is enough to calculate the value, since only relative rather than absolute values are significant in paragraph 5 belowat every step. This shortens the calculation process.
2. For each essential test, the probability of failure in the tested subset is calculated:
3. For each essential test ti, find the costs associated with ittaking into account the fact that the sequence of tests s(0) has been carried out. Testing costs can go up or down.
4. For each test ti determine the values:
.
5. Choose a test tk for which minimal: 
.
6. The tk test is applied if:
a) tk succeeds, then it comes down to finding the failed element in the subset
b) tk ends unsuccessfully, then the task is reduced to finding the failed element in the subset:
If the subset W(1) consists of one element, then the search for the failed element ends.
7. A new sequence of applied tests s(1) is fixed, which contains the previous sequence s(0) and the last applied test tk.
8. To the subset W(1), starting from item 1, the verification procedure is applied with the corresponding replacement of the upper index (0) by the index (1). The verification procedure continues until, in item 6, at some step k, a subset W(k) is formed, which consists of a single element.
Example 1 The system consists of 8 elements and can be verified by 6 tests, which are described in Table 18.1. Known costs for testing: С1=1; c2=2; C3=1.2; C4=1.5; C5=2.5; C6=1.3, the value of Ci does not depend on the order of application of the test.
Table 18.1 - Test Matrix
|
Number |
Item number |
|||||||
|
test |
||||||||
According to ch. 3.6. PTEEP "Guidelines for testing electrical equipment and devices of electrical installations of Consumers" the terms of testing and measuring the parameters of electrical equipment of electrical installations are determined by the technical manager of the Consumer on the basis of Appendix 3 of the Rules, taking into account the recommendations of factory instructions, the state of electrical installations and local conditions. The frequency of tests indicated for certain types of electrical equipment is recommended and can be changed by the decision of the technical manager of the Consumer.
Acceptance test standards must comply with the requirements of Section 1 " General rules» Chapter 1.8. "Norms for acceptance tests" of the Electrical Installation Rules (seventh edition).
In accordance with PTEEP (Appendix 3), measurements of the insulation resistance of elements electrical networks are carried out at the following times:
electrical wiring, including lighting networks, in especially dangerous premises and outdoor installations once a year, in other cases 1 time in 3 years;
cranes and elevators once a year;
stationary electric stoves 1 time per year when the stove is heated.
In other cases, tests and measurements are carried out at intervals determined in the system of preventive maintenance (PPR) approved by the technical manager of the Consumer (clause 3.6.2. PTEEP).
For example, for healthcare facilities, according to intra-industry guidance documents, the following testing periods are defined:
checking the condition of the elements of the grounding device in the first year of operation, then at least once every three years;
checking the continuity of the circuit between the ground electrode and the grounded electromedical equipment at least once a year, as well as when rearranging the electromedical equipment;
grounding device resistance at least once a year;
checking the impedance of the phase-zero loop when the network is commissioned and periodically at least once every five years.
The frequency of preventive tests of explosion-proof electrical equipment is established by the Consumer responsible for the electrical equipment, taking into account local conditions. It should be no less than indicated in the chapters of the PTEEP related to the operation of general-purpose electrical installations.
For electrical installations in explosive areas with voltage up to 1000 V with a dead-earthed neutral (TN systems), during major, current repairs and overhaul tests, but at least 1 time in 2 years, the total resistance of the phase-zero loop of electrical receivers related to this electrical installation and connected to each assembly, cabinet, etc., and check the multiplicity of the short-circuit current, which ensures the reliability of the operation of protective devices.
Unscheduled measurements should be carried out in case of failure of the protection devices of electrical installations. After each rearrangement of electrical equipment, before turning it on, it is necessary to check its connection to the grounding device, and in a network with voltage up to 1000 V with a solidly grounded neutral, in addition, the resistance of the phase-zero loop.
Specific terms for testing and measuring the parameters of electrical equipment of electrical installations during overhaul (K), during current repairs (T) and during turnaround tests and measurements (preventive tests) performed to assess the state of electrical equipment without bringing it out for repair (M), are determined by the technical manager of the Consumer , based on PTEEP and various intersectoral guidance documents.
Below is a table corresponding to Appendix 3 PTEEP and other NTD.
| № n\n |
Equipment identification | Type of equipment testing | Periodicity | Scope of preventive tests | Note | NTD |
|---|---|---|---|---|---|---|
| 1 | Oil-filled bushings | - | a) measurement of insulation resistance; (9.1) b) measurement of dielectric loss angle tg; (9.2) c) testing with increased voltage of industrial frequency; (9.3) d) testing of transformer oil (9.5) |
- | PTEEP Appendix 3 p.9 |
|
| M (between overhaul tests) | 1 time in 4 years | P.P. A); G) | - | |||
| K (for overhaul) | 1 time in 8 years | P.P. A); b); V); | - | |||
| 2 | Overhead power lines | P (before commissioning) | - | a) control of insulators; (7.8) b) measurement of the resistance of supports and cables, as well as re-grounding of the neutral wire; (7.10) c) checking the operation of line protection up to 1000 V with grounded neutral |
- | PTEEP Appendix 3 p.7 |
| M (between overhaul tests) | 1 time in 6 years | P.P. A); b); | - | |||
| 3 | Oil and electromagnetic switches | P (before commissioning) | - | a) measurement of insulation resistance; (10.1) (10.2) c) test bushings (10.3) d) measurement of resistance to direct current; (10.5) e) checking the operation of the free trip mechanism; (10.8) f) checking the operation of the drive at low voltage; (10.10) g) repeated making and breaking test (10.11) h) testing of transformer oil; (10.12) |
- | PTEEP Annex 3 p.10 |
| M (between overhaul tests) | 1 time in 4 yearsP.P. a), d), e), h) | - | ||||
| K (for overhaul) | 1 time in 8 years | P.P. a), b), c), d), e), f), g), h) | - | |||
| 4 | Air circuit breakers | - | a) measurement of insulation resistance; (11.1) b) testing with increased voltage of industrial frequency; (11.2) c) measurement of resistance to direct current; (11.3) d) checking the operation of the drive at low voltage; (11.4) e) checking the characteristics of the circuit breaker (11.5) f) repeated making and breaking test (11.6) g) testing of voltage divider capacitors (11.7) |
- | PTEEP Appendix 3 p.11 |
|
| M (between overhaul tests) | 1 time in 4 years | P.P. a), c), d), e) | - | |||
| K (for overhaul) | 1 time in 8 years | P.P. a), b), c), d), e), f), g) | - | |||
| 5 | SF6 circuit breakers 110 kV | P (before commissioning) | - | a) measurement of insulation resistance; (12.1) b) testing of insulation with increased voltage of industrial frequency; (12.2) c) measurement of resistance to direct current; (12.3) d) checking the minimum operating voltage of the switches (12.4) e) testing capacitors of voltage dividers (12.5) g) tests of built-in current transformers (12.9) |
- | PTEEP Annex 3 p.1 2 |
| M (between overhaul tests) | 1 time in 4 years | P.P. a), b), c) g) | - | |||
| K (for overhaul) | 1 time in 8 years | P.P. a), b), c), d), e), g) | - | |||
| 6 | Vacuum switches 10 kV | P (before commissioning) | - | a) measurement of insulation resistance; (13.1) b) testing with increased voltage of industrial frequency; (13.2) c) checking the minimum operating voltage of the switches (13.3) d) multiple test (13.4) e) checking the characteristics of the circuit breaker (13.5) |
- | PTEEP Appendix 3 p.13 |
| M (between overhaul tests) | 1 time in 5 years | P.P. A) | First test after 2 years | |||
| K (for overhaul) | 1 time in 10 years | P.P. a B C D E) | ||||
| 7 | Load break switches | P (before commissioning) | - | a) measurement of insulation resistance; (14.1) b) testing with increased voltage of industrial frequency; (14.2) c) DC resistance measurement (14.3) d) determination of the degree of wear of arc-suppressing liners; (14.4) e) determination of the degree of burning of contacts; (14.5) e) checking the operation of the free trip mechanism; (14.6) g) checking the operation of the drive at low voltage; (14.7) h) repeated making and breaking test (14.8) |
- | PTEEP Appendix 3 p.14 |
| M (between overhaul tests) | 1 time in 4 years | P.P. A) | - | |||
| K (for overhaul) | 1 time in 8 years | - | ||||
| 7.1 | Automatic switches | P (before commissioning) | - | a) insulation resistance measurement b) testing with increased voltage of industrial frequency; c) determination of the characteristics of the circuit breaker d) determination of the degree of wear of arc-suppressing liners; e) determination of the degree of burning of contacts; e) checking the operation of the free trip mechanism; g) checking the operation of the drive at low voltage; h) test by repeated switching on and off |
- | - |
| - | K (for overhaul) | 1 time in 8 years | P.P. a), b), c), d), e), f), g), h) | -- | ||
| 8 | Grounding devices | a) checking the connections of grounding conductors with grounded elements; (26.1) b) measurement of resistance of grounding devices; (26.4) c) the impedance of the "PHASE-ZERO" loop |
Point c) in installations up to 1000 V at least 1 time in 6 years | PTEEP Appendix 3 p. 26 |
||
| M (between overhaul tests) | 1 time in 12 years | P.P. A); b) | - | - | ||
| 1 time in 6 years | P. c) | - | - | |||
| 1 time in 12 years | P.P. a B C) | - | - | |||
| 9 | Lightning protection devices | - | Once a year before a thunderstorm | a) measurement of resistance of grounding devices; | - | - |
| 10 | PROTECTIVE EQUIPMENT | - | - | a) high voltage test | - | Rules for the use and testing of protective equipment Appendix No. 5 |
| 10.1 | Dielectric bots | M (between overhaul tests) | 1 time in 3 years | P. a) | - | |
| Dielectric galoshes | M (between overhaul tests) | 1 time per year | P. a) | - | ||
| Insulating pliers | M (between overhaul tests) | 1 time in 2 years | P. a) | - | ||
| Insulating caps | M (between overhaul tests) | 1 time per year | P. a) | - | ||
| Insulating pads | M (between overhaul tests) | 1 time in 2 years | P. a) | - | ||
| Rubber gloves (dielectric) | M (between overhaul tests) | 1 time in 6 months | P. a) | - | ||
| UVN non-contact type | M (between overhaul tests) | 1 time in 2 years | P. a) | - | ||
| UVN with gas discharge lamp | M (between overhaul tests) | 1 time per year | P. a) | - | ||
| Voltage indicators up to 1000 V | M (between overhaul tests) | 1 time per year | P. a) | - | ||
| Voltage indicators for phase matching | M (between overhaul tests) | 1 time per year | P. a) | - | ||
| 10.11 | Cable fault indicator (light signal) | M (between overhaul tests) | 1 time per year | P. a) | - | - |
| 10.12 | Cable puncture device | M (between overhaul tests) | 1 time per year | P. a) | - | |
| 10.13 | Insulating rods | M (between overhaul tests) | 1 time in 2 years | P. a) | - | |
| 10.14 | Measuring rods | M (between overhaul tests) | 1 time per year | P. a) | - | |
| 10.15 | Clamp meters | M (between overhaul tests) | 1 time in 2 years | P. a) | - | |
| 10.16 | Other means of protection, isolating devices for repair work under voltage in electrical installations of 100 kV and above | M (between overhaul tests) | 1 time per year | P. a) | - | |
| 10.17 | Suspension and support insulators | P (before commissioning) | - | b) high voltage tests; (8.2) |
- | PTEEP Appendix 3 p.8 |
| K (for overhaul) | 1 time in 8 years | P.P. a), b) | - | |||
| 10.18 | Portable electrified tool and safety step-down transformers | P (before commissioning) | - | a) measurement of insulation resistance; (28.1) b) high voltage insulation test (28.2) | - | PTEEP Annex 3 p.28 |
| M (between overhaul tests) | 1 time in 6 months | P. a) with an idle test (if possible) | Tool | |||
| 1 time per year | P. b) | transformers | ||||
| K (for overhaul) | As needed | P.P. A); b) | - | |||
| 10.19 | Test benches stationary, mobile, portable | P (before commissioning) | - | a) measurement of insulation resistance; (27.1) b) high voltage test; (27.2) c) checking the serviceability of measuring devices and test facilities; (27.3) d) checking the operation of blocking and grounding devices, signaling means (27.4) | - | PTEEP Appendix 3 p.27 |
| M (between overhaul tests) | 1 time per month | P. d) | - | |||
| 1 time in 6 years for stationary installations, 1 time in 2 years for other installations | P.P. A); b); V); G) | - | ||||
| 11 | Cable lines (power) | P (before commissioning) | - | a) determination of the integrity of the cable cores (6.1) b) measurement of insulation resistance; (6.2) c) tests with increased rectified voltage; (6.3) |
- | PTEEP Appendix 3 p.6 |
| M (between overhaul tests) | 1 time in 3 years | P.P. A); b); V) | - | |||
| K (for overhaul) | 1 time in 6 years and in case of cable breakdown | P.P. A); b); V) | - | |||
| 12 | Complete switchgears (KRU and KRUN) | P (before commissioning) | - | a) measurement of insulation resistance; (22.1) b) testing with increased voltage of industrial frequency; (22.2) c) checking the alignment and entry of moving contacts into fixed ones (22.3) d) measurement of resistance to direct current; (22.4) |
- | PTEEP Appendix 3 p.22 |
| M (between overhaul tests) | 1 time in 3 years | P.P. A); V) | - | |||
| K (for overhaul) | 1 time in 6 years | P.P. A); b); V); G) | - | |||
| 13 | Power capacitors | P (before commissioning) | a) verification appearance and sizes; (4.1) b) measurement of insulation resistance; (4.2) c) test with increased voltage of industrial frequency; (4.3) d) measurement of the capacitance of an individual element; (4.4) e) measurement of dielectric loss angle tg; (4.5) |
- | PTEEP Appendix 3 p.4 |
|
| T (for current repairs) | 1 time per year | P.P. A); b); G); | - | |||
| K (for overhaul) | 1 time in 8 years | P. P. a); b); V); G); e) | - | |||
| 14 | OIL TRANSFORMER | - | - | - | - | RD 34.45-51..300-97 "Volume and norms tests electro equipment" Section 25. |
| 14.1 | Power transformers | P (before commissioning) | - | a) breakdown voltage measurement; b) measurement of dielectric loss angle tg; |
P. b) for TR-ROV 220 kV | |
| M (between overhaul tests) | 1 time in 3 years | P.P. A) | P. b) for TR-ROV 220 kV | |||
| When gas protection is triggered | P.P. a) and gas analysis | - | - | |||
| K (tests during overhaul) | Section 1 | P.P. A); b) | - | |||
| 14.2 | Measuring transformers | M (between overhaul tests) | 1 time in 3 years | a) breakdown voltage measurement; b) measurement of dielectric loss angle tg; | - | |
| With an increase in tg of the winding insulation | P. b) | P. b) for TR-ROV current 220 kV | - | |||
| 14.3 | Oil switches | During major, current and unscheduled repairs with the number of limit shutdowns 7 and > | - | a) breakdown voltage measurement | - | - |
| 14.4 | DC machines | P (before commissioning) | - | a) measurement of winding insulation resistance; b) testing with increased voltage of industrial frequency; c) measurement of resistance to direct current; d) checking the operation of the machine at idle |
- | PTEEP Annex 3 p.24 |
| T (for current repairs) | 1 time per year | P. a) | - | |||
| K (for overhaul) | 1 time in 2 years | P.P. A); b); V); G) | - | |||
| 15 | MEASURING TRANSFORMERS | - | - | - | - | |
| 15.1 | Current transformers | P (before commissioning) | - | a) measurement of winding insulation resistance; (20.1) b) measurement tg of the dielectric loss angle of the windings; (20.2) c) testing of insulation with increased voltage of frequency 50 Hz; (20.3) d) removal of magnetization characteristics; (20.4) e) Checking the transformation ratio (20.5) f) measurement of resistance of windings to direct current; (20.6) g) Transformer oil tests (20.7) |
- | PTEEP Appendix 3 p.21 |
| 1 time in 6 years | P.P. A); b); V); G); e) | Point d) 1 time in 3 years | ||||
| K (for overhaul | As needed and test results | P.P. A); b); V); G); e) | - | |||
| 16 | POWER TRANSFORMERS AND AUTO TRANSFORMERS | - | - | - | - | PTEEP Annex 3 p.2 |
| 16.1 | Main substation transformers | P (before commissioning) | - | a) measurement of the insulation resistance of the windings; (2.2) b) measurement tg of the dielectric loss angle of the winding insulation; (2.3) c) measurement of resistance of windings to direct current; (2.5) d) checking the transformation ratio; (2.6) e) checking the winding connection group; (2.7) g) testing of transformer oil; (2.13) h) measurement of current and losses XX; (2.8) i) testing of insulation with increased applied voltage of industrial frequency; (2.4) j) testing of transformers by switching on with a push to the rated voltage; (2.14) k) thermal imaging survey; (2.21) l) assessment of the state of the switching device; (2.9) m) testing the tank for density; (2.10) o) checking the indicator silica gel; n) phasing of transformers |
- | |
| M (between overhaul tests) | 1 time in 2 years | P.P. A); b); V); and); O) | P. a) 1 time in 4 years | |||
| K (tests during overhaul) | Depending on the technical condition | P.P. A); b); V); G); e); and); h); And); To); l); m); n); O); P) | P.P. A); b); V); e); and); h); check before withdrawing to cap. repair | |||
| 16.2 | Other transformers (10/0.4) | P (before commissioning) | - | |||
| M (between overhaul tests) | 1 time in 4 years | P.P. A); V); m); O) | - | |||
| K (for overhaul) | As required, depending on the technical condition | P.P. A); V); G); e); and); h); And); To); m); O); P) | Items a); V); e); and); h); check before withdrawing to cap. repair | |||
| 17 | Fuses, fuse-disconnectors | P (before commissioning) | - | a) test of the supporting insulation with increased voltage (15.1) b) determination of the integrity of fuse-links (15.2) c) measuring the DC resistance of the current-carrying part of the exhaust fuse holder; (15.3) d) checking the fuse-disconnector by switching on and off 5 times (15.6) |
- | PTEEP Appendix 3 p.15 |
| K (for overhaul) | 1 time in 8 years | P.P. a B C D) | - | |||
| 18 | Valve arresters and surge arresters | P (before commissioning) | - | a) resistance measurement (17.1) b) measurement of the conduction current of the arrester elements; (17.3) c) measurement of breakdown voltages of arresters (17.6) |
- | PTEEP Appendix 3 p.17 |
| M (between overhaul tests) | Once a year (before a thunderstorm) | P.P. a), b) | - | |||
| K (for overhaul) | 1 time in 8 years | P.P. a B C) | - | |||
| 19 | Disconnectors, separators and short circuiters | P (before commissioning) | - | a) measurement of insulation resistance; (16.1) b) high voltage tests; (16.2) c) DC resistance measurement (16.3) d) test by switching on and off 5 times (16.5) e) determination of time characteristics (16.6) e) checking the operation of the mechanical interlock (16.7) |
- | PTEEP Appendix 3 p.16 |
| K (tests during overhaul) | 1 time in 8 years | P.P. a B C D E F) | - | |||
| 20 | Tires are prefabricated and connecting, GRU and RU cells | P (before commissioning) | a) measurement of insulation resistance; (8.1) b) high voltage test (8.2) |
- | PTEEP Appendix 3 p.8 |
|
| K (for overhaul) | 1 time in 6 years | P.P. a), b) | - | |||
| 21 | AC motors | P (before commissioning) | - | a) measurement of the insulation resistance of the electric motor; (23.1) b) high voltage test with a frequency of 50 Hz; (23.3) c) measurement of resistance to direct current; (23.4) d) measurement of gaps between the steel of the rotor and the stator; (23.5) e) checking the operation of the electric motor at idle; (23.7) f) checking the operation of the electric motor under load; (23.10) g) checking the operation of machine protection up to 1000 V with a power supply system with a grounded neutral |
- | PTEEP Appendix 3 p.23 |
| M (between overhaul tests) | 1 time in 3 years | P.P. A); b); and); V); e) | ||||
| K (tests during overhaul) | - | P.P. A); b); V); G); e); e); and) | ||||
| 22 | Wiring up to 1000 V | P (before commissioning) | - | a) measurement of insulation resistance; (28.1) b) high voltage insulation test (28.2) c) measurement of the resistance of the phase-zero loop (28.4) |
- | PTEEP Annex 3 p.28 |
| T (tests during current repairs) | 1 time in 6 years | P.P. A) | ||||
| K (for overhaul) | 1 time 12 years | P.P. A); b) | ||||
| 23 | Measurement of loop resistance phase zero and insulation resistance of explosion-proof equipment 0.4 kV | P (before commissioning) | |
- | PTEEP Annex 3 p.28 |
|
| M (between overhaul tests) | 1 time in 2 years | P.P. A); b) | - | |||
| K (tests during overhaul) | 1 time in 8 years | P.P. A); b) | - | |||
| 24 | Measurement of loop resistance phase zero and insulation resistance of equipment of normal execution (non-explosion-proof) | P (before commissioning) | - | a) measurement of insulation resistance; (28.1) b) measurement of the resistance of the phase-zero loop (28.4) |
- | PTEEP Annex 3 p.28 |
| M (between overhaul tests) | 1 time in 4 years | P.P. A); b) | - | |||
| K (tests during overhaul) | 1 time in 8 years | P.P. A); b) | - |
Electrical equipment is regularly tested, which pursue the goal of verifying compliance with established technical specifications, obtaining data for carrying out the following preventive tests, establishing the absence of defects, as well as for studying the operation of electrical equipment. There are such types of tests: operational, acceptance, control, standard, special.
Type tests are used for new equipment, which differs from old models in an updated design, device. This type of test is carried out by the manufacturer in order to verify compliance with all requirements and standards that apply to this type of equipment, or specifications.
To check the compliance of the manufactured product with all the main technical requirements, each product is subjected to control tests (apparatus, machine, device, etc.). For control tests, as a rule, an abbreviated program of work is used (compared to standard ones).
Acceptance tests are used after the installation of newly commissioned equipment is completed in order to assess its suitability for operation.
Performance tests are carried out for equipment that is in operation, including those that have been out of repair. This type of test serves to determine the health of the equipment. Operational tests include tests at current, overhauls, as well as preventive tests that are not related to the withdrawal of equipment for repair.
For research purposes or other special programs, special tests may be carried out.
Some part of the test work is carried out similarly for almost all elements of electrical equipment. These types of work include: testing and, control of electrical connection diagrams.
When checking wiring diagrams, the following actions are carried out:
1) familiarization with the technical information on the object - the installation and basic (complete) switching diagrams, cable magazine are studied;
2) checking for compliance with the project of real equipment and equipment;
3) verification and inspection of the conformity of cables and wires (section, material, brand, etc.) current rules and the project
4) control of the correctness and presence of marking on the cores of cables and wires, terminals of devices, terminal blocks;
5) quality control of installation (laying cables, laying cables on panels, reliability of contact connections, etc.);
6) continuity (control of the correct installation of circuits);
7) testing the reliability of electrical circuits when voltage is applied.
The most comprehensive tests in the primary and secondary switching circuits are carried out during acceptance tests after installation is completed. During preventive tests, the number of switching control operations is significantly reduced. Installers or adjusters must eliminate deviations from the design or installation errors discovered during the inspection. In order to change or deviate from the project, you must first obtain the consent of the design organization. Any such modifications must be provided in the form of drawings.
Loading...