GB 20840.4-2015Instrument transformers -- Part 4: Additional requirement for combined transformers (English PDF)

3.1 General definitions

3.1.401

Combined Transformer combinedinstrumenttransformer A combination of current transformers and voltage transformers integral transformers.

3.1.402

Voltage transformer voltage error voltageerrorofvoltagetransformer epsilonv when the ratio of the current transformer voltage transformer did not pass current determining the difference.

3.1.403

Phase voltage transformer phasedisplacementofvoltagetransformer deltav when the current transformer voltage transformer did not pass current determining retardation.

3.1.404

Rated continuous influenza should thermoelectric voltage voltageinducedbyratedcontinuousthermalcurrent Uv Current transformer rated continuous thermal current in the voltage transformer induced voltage, error is defined as a measure of the maximum amount of change.

3.1.405

The maximum amount of change of the voltage error greatestvariationofvoltageerror deltaepsilonv Current transformer rated continuous influenza should thermoelectric voltage maximum amount of change caused by the voltage transformer ratio difference possible.

3.1.406

The maximum amount of change in voltage transformer phase difference greatestvariationofphasedisplacement deltadeltav Current transformer rated continuous influenza should thermoelectric voltage phase voltage transformer caused the maximum possible amount of change.

3.1.407

Integrated voltage error of the absolute value of absolutevalueofthevariationsofvoltageerror epsilon'v the ratio of the difference between the maximum amount of change in voltage at a predetermined voltage error voltage transformer with both the absolute value of the sum.

3.1.408

Phase voltage transformer integrated absolute value absolutevalueofthevariationsofphasedisplacementofvoltagetrans-former delta'v the maximum amount of change with a predetermined phase retardation voltage transformer, both the absolute value of the sum.

3.1.409

Rated short influenza should thermoelectric voltage voltageinducedatratedshort-timethermalcurrent Ue Current transformer rated short-time thermal current in the voltage transformer voltage induced on the nameplate.

3.1.410

Current transformer current error currenterrorofcurrenttransformer epsiloni when the ratio of the current transformer voltage transformer unexcited determined difference.

3.1.411

Current transformer phase phasedisplacementofcurrenttransformer deltai Current transformers for voltage transformer unexcited determine retardation.

3.1.412

Current transformer capacitive current voltage generated voltagegeneratedinthecurrenttransformerbycapacitivecurrent Ui Voltage transformer voltage is applied to generate a voltage across the capacitor current generated in the current transformer, the current error is defined as the maximum amount of change Measure.

3.1.413

The maximum amount of change greatestvariationofcurrenterror current error deltaepsiloni Capacitive current generated by the current transformer voltage caused by the current transformer ratio difference between the maximum possible amount of change.

3.1.414

The maximum amount of change of phase current transformers greatestvariationofphasedisplacement deltadeltai Capacitive current generated by the current transformer current transformer voltage caused retardation maximum possible amount of change.

3.1.415

Integrated absolute value of the current error absolutevalueofthevariationsofcurrenterror epsilon'i Current error maximum change in current transformer ratio difference with a predetermined current, the sum of the absolute values of both.

3.1.416

The absolute value of the current transformer phase synthesis absolutevalueofthevariationsofphasedisplacementofcurrenttrans-former delta'i the maximum amount of change with a predetermined phase retardation current transformer, both the absolute value of the sum.

3.7 Symbol and Name

GB 20840.1-2010 3.7 with the following alternatives.

epsilonv voltage transformer voltage error deltav phase voltage transformer Uv rated continuous voltage corresponding thermoelectric flu the maximum amount of change of the voltage error deltaepsilonv Rated secondary voltage Usr the maximum amount of change of phase voltage transformer deltadeltav Integrated voltage error of the absolute value of epsilon'v Integrated absolute value of the phase difference between the voltage transformer delta'v Rated short-time thermal current Ith Icth rated continuous thermal current Ue rated short influenza should thermoelectric voltage epsiloni current transformer current error deltai phase current transformer Voltage Ui current transformer capacitive current generated the maximum amount of change deltaepsiloni current error the maximum amount of change of phase current transformers deltadeltai Integrated absolute value of the current error epsilon'i Integrated current transformer phase difference absolute value delta'i Isr rated secondary current

5.401.1 General requirements

Combination transformer measuring error limits, should be consistent with GB 20840.2-2014 in 5.6.201 measuring current transformer requirements and GB 20840.3-2013 in 5.6.301 for measuring voltage transformer requirements. Transformer protection with a combination of error limits, should be consistent GB 20840.2-2014 in 5.6.202 of protective current transformer and GB 20840.3-2013 requirements for the protection of electricity in 5.6.302 Pressure transformer requirements.

5.401.2 Interaction

When the current transformer to run between 5% of the rated current and the rated thermal current, voltage transformer at a predetermined load range and in Between 80% and 120% of rated voltage, the voltage and phase error should not exceed the limits of their respective accuracy class.

When the voltage between the transformer due to multiple rated voltage operation at 80% of rated voltage and rated voltage, current transformer at a predetermined negative Charge current range and range accuracy class requirements, the current error and phase accuracy class shall not exceed the corresponding limits.

See 7.2.6.401 and 7.2.6.402 and Appendix 4C.

6.4 Pairs of parts and components of the temperature requirements

6.4.1 General requirements

GB 6.4.1 with the following additions to the content 20840.2-2014 apply.

If the voltage is applied in line with GB 20840.3-2013 specified in 7.2.2, and the current transformer primary current carried by the rated continuous Thermal current, the combined transformer temperature rise should not exceed the values specified in 6.4 GB 20840.1. At this time, the current transformer connected to power 1 load factor corresponding to the rated output voltage transformer and connect power factor of 0.8 (lagging) to 1 between rated load, or A plurality of rated load maximum rated load. 10K additional margin of voltage transformer under certain circumstances permit (see GB 20840.3-2013 7.2.2) also applies to the combination of the current transformer.

6.13 Mark

6.13.401 Terminal markings

Combined Transformer current transformer and voltage transformer terminal markings alone the same transformer, marked a manner in accordance with GB 20840.2-2014 GB 20840.3-2013 in 6.13.201 and 6.13.301 of the regulations.

6.13.402 Nameplate

6.13.402.1 Universal Content

Current transformer nameplate shall GB 20840.2-2014 Technical characteristics of the mark in 6.13.202, voltage transformer nameplate shall Technical characteristics according to GB 20840.3-2013 in 6.13.302 of the mark.

6.13.402.2 Combination transformer nameplate

Nameplate shall be marked with the current flowing through the transformer rated short-time thermal current root-mean-square value of the induced voltage transformer voltage Ue value, in which case electricity Voltage transformer primary winding shorted. This induced voltage is measured at the terminals connected to the voltage transformer 15VA or secondary winding rated load Obtained.

401 Note. Instead rated short-time thermal current root-mean-square value of the induced voltage Ue, nameplate marked the induced voltage and current transformer ratio of the current flowing to each Millivolt kA representation.

7.1 General requirements

7.1.2 Test Project

Table 11 replaced with the following.

Table 11 pilot projects

Test Clause No.

Type Test 7.2

Temperature Rise Test 7.2.2 One end of the impulse withstand voltage test 7.2.3 Outdoor transformer and humidity test 7.2.4 Electromagnetic compatibility (EMC) test 7.2.5

7.2.6 Accuracy Test

7.2.7 Test enclosure class

Sealing performance test (for gas-insulated products) at ambient temperature 7.2.8 Pressure test (applicable to gas-insulated products) 7.2.9 Short-time current test 7.2.201 Short circuit withstand capability test 7.2.301 Routine tests 7.3 Gas dew point measurement (applicable to gas-insulated products) 7.3.1 One end of the power frequency voltage withstand test 7.3.2 Partial discharge measurement 7.3.3 Capacitance and dielectric loss factor measurement 7.3.4 Inter-segment frequency voltage withstand test 7.3.5 Secondary end frequency voltage withstand test 7.3.6

7.3.7 Accuracy Test

7.3.8 Test mark

Ambient temperature sealing performance test 7.3.9 Pressure test (applicable to gas-insulated products) 7.3.10 Secondary winding resistance (Rct) Determination 7.3.201

Table 11 (continued)

Test Clause No.

Secondary circuit time constant (Ts) measured 7.3.202 Rated inflection potential (Ek) and the lower Ek excitation current test 7.3.203 Inter-turn overvoltage test 7.3.204 Excitation characteristic measurement 7.3.301 Insulating oil Performance Test 7.3.205 or 7.3.302 Special test 7.4 One end of the truncated impulse withstand voltage test 7.2.3.301 and 7.4.1 Repeatedly cut off one end of the impact test 7.4.2 Pass overvoltage tests 7.4.3 Mechanical strength test 7.4.4 Internal arc fault test 7.4.5 Sealing performance test (for gas-insulated products) under low and high temperature 7.4.6

7.4.7 Corrosion Test

Fire hazard testing 7.4.8

7.5 Sampling Test

Remanence coefficient measurement 7.5.1 Measuring current transformer measurement instrument security factor (FS) 7.5.2

7.2 Type tests

7.2.2 Temperature Rise Test

GB 20840.1-2010 7.2.2 the first sentence with the following alternatives.

The test is to verify compliance with the requirements of 6.4.1.

GB 20840.1-2010, GB 20840.2-2014 GB 20840.3-2013 7.2.2 and the content of the following additions apply.

When there is a plurality of secondary windings, in addition to manufacturing and users agree otherwise, the test should be connected to the respective load rating in each of the secondary windings get on. To test, combined transformer installation should represent the state of its runtime installed. Current and voltage is applied simultaneously to the provisions of A combination of the transformer. To this end, the current transformer supplying large current transformer, the primary and secondary windings with each other in accordance with the grid should Full voltage insulation.

If no such transformers, it is recommended that the other two pilot programs.

a) a combination of the insulation transformer installation. A high voltage is applied to the terminal while the seat frame, the enclosure, the primary winding operation are generally intended to ground and one terminal of each secondary winding and the primary winding connected to the operation of the proposed power line terminals are grounded. Thereby supplying a large electric Flow of high-voltage transformer does not require insulation.

b) a high voltage is applied to the operation of the proposed power line connected to the terminal. A high voltage terminals shorted and connected to the current transformer. by or a plurality of secondary windings are energized current transformer short-circuited primary winding obtained Rated continuous thermal current.

The results of all three methods are the same, is determined by the selection method of manufacturing.

The temperature rise of the winding resistance measurement should be used. For small values of the current transformer primary winding resistance can be measured using a thermocouple.

Winding temperature than other parts of the available thermometer or thermocouple measurement.

7.2.3 a side impact pressure test

7.2.3.1 General requirements

GB 20840.1-2010, GB 20840.2-2014 GB 20840.3-2013 in 7.2.3.1 and the content of the following additions apply.

Shock wave voltage to be applied to short-circuit the current transformer primary winding and voltage transformer primary winding connected to the operation of the proposed high-voltage terminal on. This wiring method is also applicable to the truncated lightning impulse test and multiple truncated lightning impulse test.

7.2.6 Accuracy test

Effect 7.2.6.401 current transformer voltage transformer Combined transformer, the effect of the current transformer voltage transformer should test the following requirements.

Current transformer power supply wire should be formed with the primary terminals with high levels of circuit (see FIG. 401). Figure 401 with a return showing it shall be equal to the distance from the conductor phase power line. The rest of the current loop, respectively, each length should be at least 1.6m. Voltage transformer the primary winding short circuit wiring ...