This standard only specifies the special performance requirements for converter transformers. GB/T 3859.3-1993 Semiconductor converter transformers and reactors GB/T3859.3-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Semiconductor Converters Transformers and Reactors
Semiconductor Converters Transformers and Reactors GB/T 3859.3—93
Replaces GB3859-83
This standard is equivalent to IEC-1-3 (1991) Semiconductor Converters: General Requirements and Power Grid Phase-commutated Converters Part 3: Transformers and Reactors.
1 Scope
The instruments specified in this standard are special performance requirements for converter transformers. Therefore, the common requirements for transformers should refer to GB1094 and JB2530 and the provisions of IEC transformer standards. Normally, rectifier transformers operate under non-stop current waveforms. When single-beat connection is used, the current of each valve-side winding contains a DC component, which should be paid special attention to during design and testing. In some cases, external short circuits and component failures may cause abnormal stress, requiring special design.
For some types of transformers, the voltage waveform during normal operation is not sinusoidal. In this case, the iron loss of the equipment can be determined by applying a sinusoidal voltage, the half-cycle arithmetic mean and fundamental frequency of which should be the same as the voltage during operation. 2 Related standards
GB1094 Power transformer
GB/T3859.1 Semiconductor converter
Basic requirements
GB/T3859.2 Semiconductor converter
Application guidebzxz.net
JB2530 Converter transformer
3 Converter transformer rating
3.1 Rated current value
3.1.1 When the maximum cooling temperature of a single converter or dual converter powered by a common valve-side winding does not exceed its thermal limit, the converter transformer shall be able to continuously withstand a current corresponding to the rated current of the converter, and thereafter withstand an overload current (specified value) for a specified duration (see Article 5.6.3 of GB/T3859.1). 3.1.2 For a dual converter in which each thyristor device has an independent valve-side winding, when the maximum cooling temperature does not exceed its thermal limit, each secondary winding of the converter transformer shall be able to continuously withstand the corresponding current corresponding to the rated DC current of the converter, and then withstand the specified overload current for the specified duration (see G/T3859.1 Section 5.6.3).
*1FC76 power transformer.
Approved by the State Administration of Technical Supervision in 1993-1227
Implementation on September 1, 1994
GB/T 3859. 3-93
When two valve-side windings share a grid-side winding, the determination of their rated current is the same as in Section 3.1.1. 3-2 Temperature limit of cooling medium
For the temperature rise limit, see Section 5.3. When there is a discrepancy between the provisions of this standard and JB2530, the supply and demand parties may negotiate to resolve the problem. 3.2.1 Outdoor air cooling equipment
Transformers should be designed to operate at an ambient air temperature not exceeding 40°C, with an annual average temperature not exceeding 20°C and any 24-hour average temperature not exceeding 30°C
3.2.2 Indoor air cooling equipment
Transformers should be designed to operate at an ambient air temperature not exceeding 40°C. 3.2.3 Water cooling equipment
Transformers should be designed to operate at a cooling water inlet temperature not exceeding 25°C. 4 Losses and voltage drops of transformers and reactors 4.1 Losses of transformer windings
Under normal operation, the losses generated in the windings include the losses of the winding resistance measured by the DC method, and the additional losses (related to frequency) generated by eddy currents and stray magnetic flux placed in the windings and frame parts. Due to the presence of ripples, the actual loss of the windings is measured under normal operation of the transformer and the device.
Because this measurement method is too complicated and inaccurate, it is not recommended unless the total losses of the transformer and the device are measured at once. In this case, for equipment with a rated output not exceeding 300 kW, the losses can be measured in normal rated load operation. In all other cases, the winding losses are calculated from the short-circuit results with sinusoidal currents. This method is based on the assumption that the sinusoidal currents passing through the windings have the same rms value as the currents present in the windings during operation of the device, assuming that the overlap angle is negligible (see Table 2).
There is a positive error due to the fact that the rms value of the currents in the windings during normal operation of the device is slightly smaller than during the test. It is assumed that this positive error is compensated by the negative error caused by additional stray losses (harmonic generation) that are neglected during operation. 4.2 Losses of interphase transformers, current-sharing reactors, series smoothing reactors, mutual inductors and other current regulation auxiliary equipment 4.2.1 The manufacturer of balancing reactors (interphase transformers) shall measure the core losses at the frequency and voltage calculated for the flux provided. The flux corresponds to the operating conditions of the converter at rated current and voltage and specified phase control. The frequency used can be adjusted to be very close to the main frequency of the interphase transformer. The core loss of windings can be calculated by the product of the DC resistance of the windings and the square of the DC current of the windings. 4.2.2 Current-sharing reactors
The core loss of current-sharing reactors is usually negligible. Winding losses can be measured as part of the converter loss measurement or calculated by the product of the measured DC resistance of the windings and the square of the DC current of the windings, based on the fact that the current waveform is rectangular. 4.2.3 Series smoothing reactors
The core loss of windings is usually negligible.
The core loss of windings can be measured as part of the converter loss measurement or calculated by the product of the DC resistance of the windings and the square of the DC current.
4.2.4The core loss of inductors and other current regulation auxiliary equipment should be measured or calculated under the magnetic flux conditions corresponding to the converter operating at rated current, rated grid voltage and specified DC voltage. The frequency used in the measurement is the main frequency of the core flux of the transformer. The power winding loss is calculated by the product of the measured DC resistance of the winding and the square of the RMS value of the winding current, and is carried out under an ideal current waveform (ignoring stray inductance). When the power winding is wound with thick wire, the eddy current loss should be determined and accumulated by calculation.
Note: These losses are only used for efficiency calculation and are not calculated during design. 4.3 Voltage drop of transformers and reactors
GB/T 3859.3-93
The voltage drop is calculated based on the loss measurement. The calculation formula is shown in Article 5.7.3 of GB/T3859.1. 5 Tests of converter transformers
The tests specified below are only tests of the special performance parts of converter transformers: comprehensive performance tests should be carried out in accordance with the provisions of GB.1094 and JB2530. When there are differences with the provisions of this standard, the provisions of this standard shall be followed. 5.1 Measurement of commutation reactance and determination of inductive voltage drop 5.1.1 Commutation reactance
To measure the commutation reactance, the transformer grid terminals should be short-circuited. An alternating current of rated frequency is passed through two adjacent phases of the same commutation group of the valve side winding and the voltage between the terminals is measured under such feeding mode. The commutation reactance 2X, which is equal to the inductive component of the impedance calculated from this measurement, should be tested at least twice in different phase sequences of each commutation group and the arithmetic mean of these measurements should be taken. The commutation groups connected in parallel or in series can be fed by the same grid side winding and commutated simultaneously. In this case, when making the above test, the valve side windings corresponding to these commutation groups are connected in parallel with each other. 5.1.2 Inductive voltage regulation
The inductive voltage drop can be calculated from the value of X, using the following formula. dn (oqs/2 yuan g)X ·(Ian/Udu)
In the formula: g—number of commutation groups with shunt Ian; Q—number of commutation groups:
Ian rated DC current;
s—number of series commutation groups:
Uaio-—ideal no-load DC voltage:
number of commutation groups with simultaneous commutation of each primary winding. Similarly, the inductive voltage drop can also be obtained by the test described in 5.1.1. During the test, current is passed, and its effective value is: (/2/4) .(8/g)+1an
In this case, the inductive component of the input voltage is expressed in terms of the nominal value of the rated voltage U between the terminals, that is, the inductive voltage regulation rate dx1. The inductive voltage regulation rate of various connection forms listed in Table 1 can be calculated according to the results of the secondary short-circuit test specified in column 17 of Table 1. Except for the connection forms of serial numbers 3, 4, 6, 9 and 12, it is recommended to conduct the short-circuit test specified in 5.1.1 (GB/T 3859.2 Article 5.3.4) for the remaining connections.
If the secondary current is too large to use this method, any other equivalent method to form a valve side winding short circuit can be used. 5.2 Short-circuit test (type test and factory test) This test is carried out to obtain the total loss of the transformer winding. Table 1 lists the short-circuit connections suitable for the most common connection forms. The current of the transformer winding should be a sine wave, and its root mean square value is the same as the current in the grid-side conductor during normal operation at rated DC current and rated frequency (ignoring the overlap angle). The input power of the short-circuit test A, B, C = cases should be measured respectively and expressed as Pa, PB and Pc. The total loss can be calculated according to the formula given in Table 1.
The measured winding loss is corrected to the specified limit temperature value (Table 2) plus 20℃. 5.3 Temperature rise test (type test)
The temperature rise measurement of the transformer winding should be carried out after the rated load is continuously applied. The temperature rise should not exceed the value specified in Table 2. The values ​​given in Table 1 are based on the ambient temperature and cooling medium temperature specified in Article 3.2 and operation at an altitude not exceeding 1000m. When the cooling medium temperature is higher, it shall be corrected according to Appendix A of this standard. 3859.3—93
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GB/T3859.3—.93
Table 2 Temperature rise limit
Transformer cooling medium
Transformer temperature level
Winding measured by resistance method
Limit temperature rise, K
Note: ①The temperature rise value is based on the maximum ambient humidity of 40℃, the annual average temperature is not higher than 26℃ and the daily average ambient temperature is 30℃. ②If the user and the supplier reach an agreement, other transformer temperature levels can be used. At this time, if the temperature rise value cannot be found in the table, it can also be agreed upon by both parties.
③ See GB/T3859.1, Section 5.6.3.5 for the duty level. GB/T 3859.3-93
Appendix A
Transformer operation when ambient temperature and cooling medium temperature are higher than the specified value (reference)
When the ambient air temperature or cooling medium temperature exceeds the highest specified value under normal operating conditions (but not more than 15K), in order to ensure the safe operation of the transformer and reactor, the allowable limit temperature rise should be reduced accordingly, and the following table is corrected. When the cooling medium temperature is higher than the standard value, the reduction of the temperature rise limit value Transformer and reactor operation conditions
Natural air cooling and forced convection cooling
When the maximum cooling air temperature exceeds 1K
, from 5.3
Deduct from the limit given in Article 5.3 for each 1K above the annual average or daily average cooling air maximum temperature (whichever exceeds the larger value) (insulation class A)
Fluid—Water Cooling
Deduct from the limit given in Article 5.3 for each 1K above the annual average or daily average cooling air maximum temperature (whichever exceeds the larger value) (insulation class A)
Additional Notes:
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Power Electronics.
Duty Level
This standard is drafted by the Xi'an Power Electronics Technology Research Institute of the Ministry of Machinery Industry. The main drafter of this standard is Zhou Guanyun.
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