DL/T 2008-2019Field test method for power transformer, closed combination electric appliance and power cable composite connection (English PDF)

Foreword

This standard is compiled in accordance with the rules of GB/T 1.1-2009 "Guidelines for Standardization Part 1: Standard Structure and Compilation".

This standard was proposed by the China Electricity Council.

This standard is under the jurisdiction of the Power Transformer Standardization Technical Committee (DL/T C 02) of the power industry.

Drafting organizations of this standard. State Grid Liaoning Electric Power Co., Ltd. Electric Power Research Institute, State Grid Liaoning Electric Power Co., Ltd., China Electric Power Research Institute Co., Ltd., State Grid Chongqing Electric Power Company, State Grid Gansu Electric Power Company Electric Power Research Institute Research Institute, State Grid Chongqing Electric Power Research Institute, State Grid Hebei Electric Power Co., Ltd. Electric Power Research Institute, Jilin Electric Power Co., Ltd. Electric Power Research Institute, State Grid Henan Electric Power Company, China Southern Power Grid Research Institute Co., Ltd.

Ren company, Guangzhou Power Supply Bureau Electric Power Test Research Institute, Xi'an Xidian Transformer Co., Ltd., Datang Shandong Electric Power Company Limited.

1 Scope

This standard specifies power transformers, enclosed combined electrical appliances, power cables (hereinafter referred to as transformers, combined Terms and definitions, test items, test methods and requirements, test report compilation for field test of composite connection (electrical appliances, cables) Write etc.

This standard is applicable to the field test after the composite connection of transformers, combined electrical appliances and cables with voltage levels of 35kV~750kV.

Test.

2 Normative references

The following documents are indispensable for the application of this standard. For dated reference documents, only the dated version is suitable Used in this standard. For undated reference documents, the latest version (including all amendments) is applicable to this standard.

GB/T 2900.10-2013 Electrical terminology cable GB/T 2900.20-1994 Electrical terminology high-voltage switchgear GB/T 2900.95-2015 Electrotechnical terminology transformers, voltage regulators and reactors GB/T 5832.1 Determination of trace moisture in gas Part 1: Electrolysis method GB/T 5832.2 Determination of trace moisture in gas Part 2: Dew point method GB/T 8905 Guidelines for Gas Management and Detection in Electrical Equipment of Sulfur Hexafluoride GB 50150 Electrical equipment installation engineering electrical equipment handover test standard DL/T 474.4 Implementation guidelines for on-site insulation test AC withstand voltage test DL/T 506 Insulating gas humidity measurement method in sulphur hexafluoride electrical equipment DL/T 911 Frequency Response Analysis Method of Power Transformer Winding Deformation DL/T 1205 Test method for decomposition products of sulfur hexafluoride electrical equipment DL/T 1093 The guideline for detecting and judging power transformer winding deformation by reactance method DL/T 5293 Unified format of electrical equipment handover test report for electrical installation engineering JB/T 501 Power Transformer Test Guide

3 Terms and definitions

The following terms and definitions established in GB/T 2900.20, GB/T 2900.95 and GB/T 2900.10 apply to this standard quasi.

Power transformer

A static power converter that transfers power without changing the frequency of its AC power source.

[GB/T 2900.95-2015, terms and definitions 3.1.1] 3.2 Combination electrical gas insulated metal-enclosed switchgear (GIS) at least part of the metal-enclosed switchgear that uses gas above atmospheric pressure as the insulating medium.

[GB/T 2900.20-1994, terms and definitions 3.12] 3.3 Insulated cable an assembly consisting of.

--One or more insulated cores;

--Respective coating (if any);

--Cable core protective layer (if any);

-Outer protective layer (if any);

There can be additional non-insulated conductors in the cable;

[GB/T 2900.10-2013, terms and definitions 2.2.1] 3.4 Complex combination of transformer, GIS and cable (CC-TGC) Transformers, combined electrical appliances and cables adopt oil and gas bushings, gas and gas bushings, oil and oil bushings, plug-in cable terminals, etc.

Realize the combination form of transformer and combined electrical appliance connection, combined electrical appliance and cable connection, transformer and cable connection.

4 General

4.1 This standard specifies the test items and test methods that should be carried out after the handover and operation of CC-TGC.

The assessment of the installation quality of the composite connection parts and the assessment of whether the CC-TGC meets the operating conditions after it is put into operation.

4.2 During the handover test, the initial value is the factory test data; when the routine test or preventive test is put into operation, the initial value is After CC-TGC is connected, test data will be transferred.

5 Test items

6 Test methods and requirements

7 Test criteria

7.1 Test criteria for the air chamber tightness test at the composite connection part of the combined electrical appliance, transformer and cable

a) When the leak detector is used for detection, the leak detector should not alarm;

b) When the partial bandaging method is used for measurement, the test results should meet the relevant regulations of GB 8905.

7.2 Test criteria for measuring water content of SF6 gas in the gas chamber at the composite connection part of the combined electrical appliance, transformer and cable the water content of SF6 in the air chamber of the connection part shall meet the relevant regulations of GB 50150, DL/T 393 and DL/T 596.

7.3 Test criteria for measuring the decomposition products of the air chamber at the composite connection part of the combined electrical appliance, transformer and cable the content of decomposition products in the air chamber at the connection part is SO2<=1µL/L, H2S<=1µL/L.

7.4 Test criteria for measuring DC resistance of the winding and bushing on the composite connection side of the transformer

a) For three-phase transformers with voltage levels of 1600kVA and below, the mutual difference between the test values of each phase should be less than 4% of the average value.

The mutual difference between the test values should be less than 2% of the average value; for three-phase transformers above 1600kVA, the mutual difference between the test values of each phase should be less than the average 2% of the value, the difference between the test values between lines should be less than 1% of the average value;

b) The initial value difference of the same phase does not exceed ±2%;

c) When there is a significant difference compared with the actual measured value of the transformer at the same temperature, comprehensive analysis should be made.

7.5 Test criteria for measuring the insulation resistance, absorption ratio or polarization index of the transformer composite connection side winding and bushing

a) There should be no significant drop in insulation resistance;

b) The absorption ratio should not be significantly different from the initial value, and should not be less than 1.3 at room temperature;

c) There should be no significant difference between the polarization index and the initial value, and should not be less than 1.5 at room temperature;

d) When there is a significant difference between the factory-measured value of the transformer at the same temperature, a comprehensive analysis should be made.

7.6 Test criteria for the measurement of the dielectric loss factor tandelta of the transformer composite connection side winding and bushing

a) The tandelta value of the tested winding should not be greater than 130% of the initial value;

b) When there is a significant difference between the factory-measured value of the transformer at the same temperature, a comprehensive analysis should be made.

7.7 AC withstand voltage test criteria for the composite connection parts of transformers and combined electrical appliances the test results should meet the relevant regulations of GB 1094.3.If the test voltage does not drop suddenly, the test is qualified.

7.8 Criteria for AC withstand voltage test of composite connection parts of combined electrical appliances and cables the test results should meet the relevant regulations of DL/T 474.4.If the test voltage does not drop suddenly, the test is qualified.

8 Test report

See Appendix B for the test report format.

Appendix A

(Informative appendix) Test wiring when measuring the insulation characteristics of the composite connection side of the transformer A.1 Test wiring when conducting transformer insulation characteristics measurement at the grounding switch adjacent to the combined electrical appliance and the transformer Before the measurement, disconnect the circuit breaker CB that connects the transformer and the combined appliance in the combined appliance, and disconnect the isolation switch DS1.

The grounding knife switch ES1 is closed, and the short-circuit bar SJ between the conductive part of the knife switch and the grounding body is disconnected.

The three-phase conductive parts of the ground knife switch ES1 and the neutral point of the winding under test are short-circuited with a wire. At the same time, for safety, the grounding switch ES2 Put it in the grounded state, the measurement is carried out at the short circuit of the three-phase conductive part of the grounding switch ES1 and the neutral point of the tested winding, not under test the winding is short-circuited to ground, and the test wiring is shown in Figure A.1.

A.2 Test wiring when conducting transformer insulation characteristic measurement at the neutral bushing of the transformer Disconnect the circuit breaker CB, the isolating switch DS1 and the grounding switch ES1 between the transformer and the combined electrical appliance.

The group is short-circuited and grounded. The measured winding terminal does not need to be short-circuited. The measurement is carried out at the neutral point of the winding the grounding switch ES2 is placed in the grounded state, and the test wiring is shown in Figure A.2.

Figure A.2 Test wiring when conducting transformer insulation characteristics measurement at the neutral bushing of the transformer

Appendix B

(Informative appendix) Test report of composite connection of transformers, combined electrical appliances and cables B.1 Test report of composite connection of transformers, combined electrical appliances and cables

Table B.1 gives examples of typical test reports (templates) for the composite connection of transformers, combined electrical appliances and cables.

4.The insulation resistance, absorption ratio or polarization index of the winding on the composite connection side of the transformer and the bushing 5.Dielectric loss factor of the transformer composite connection side winding and bushing 6.AC withstand voltage test of composite connection part 7.Deformation test of the winding on the composite connection side of the transformer