CN205844468U - Dry-type air-core reactor turn-to-turn insulation performance test system - Google Patents

Abstract

The utility model discloses a dry-type air-core reactor turn-to-turn insulation performance test system, which comprises a high-voltage switchgear, a frequency conversion test power supply, a test transformer, a reactive power compensation unit, a partial discharge monitoring unit and a unit to be tested. The switchgear is connected to 380V three-phase AC current, and the high-voltage switchgear, frequency conversion test power supply, test transformer, reactive power compensation unit, partial discharge monitoring unit, and tested unit are connected in sequence; the partial discharge monitoring unit includes a coupling capacitor . A tester for measuring impedance and partial discharge, wherein the unit under test includes a dry-type air-core reactor and an AC voltage measurement unit, and the dry-type air-core reactor and the AC voltage measurement unit are connected in parallel. The utility model can carry out an induction withstand voltage test on a 35 kV dry-type air-core reactor on site, and complete the boost operation of the reactor on site.

Description

Dry-type air-core reactor turn-to-turn insulation performance test system

technical field

The utility model relates to the technical field of dry-type air-core reactors, in particular to a test system for inter-turn insulation performance of dry-type air-core reactors.

Background technique

With the continuous development of my country's electric power industry, how to improve the quality and reliability of power supply has become an important issue that needs to be considered by the power supply system. Reactive power compensation devices play an important role in improving the quality of power supply and have been developed rapidly in recent years; and in order to ensure the reliability of power supply and protect transformers from short-circuit current impact, short-circuit current limiting devices are also widely used.

As a representative device in reactive power compensation device and short-circuit current limiting device, dry-type air-core reactor has the advantages of low loss, low noise, small maintenance workload, less prone to phase-to-phase short-circuit faults, good linearity of reactance value, and long design life. In recent years, it has been widely used in power grid equipment at home and abroad. Common reactors used in power systems include shunt reactors and series reactors. The shunt reactor is used to absorb the capacitive reactive power of the line to improve the reactive power of the power system; the series reactor is mainly used to limit the short-circuit current, or limit the higher harmonics in the power grid by connecting in series or parallel with the capacitor .

With the large-scale application of dry-type air-core reactors in power grids, accidents caused by various defects of reactors will inevitably occur. In the statistics of reactor defects, it is found that short-circuit faults caused by inter-turn insulation occur in various Defects accounted for the highest proportion, close to half. Most of the reactor faults are caused by inter-turn short circuit, which causes the reactor to ignite and burn, which has a great impact on the safe and stable operation of the power system.

For the test research on the inter-turn insulation of dry-type air-core reactors, the research methods of domestic scholars can be roughly divided into the following types: one is the induction withstand voltage test method, which directly applies power frequency voltage to the first and last ends of the reactor, It is the closest to the actual operating condition of the reactor, and can effectively assess the ability of the reactor inter-turn insulation to withstand overvoltage, but the reactive power required by this method is very large, and it is difficult to have a test device that can meet the capacity requirements of the test, so that This method is extremely limited. One is the lightning impulse voltage test method. Due to the limitations of the induction withstand voltage test method, this method is used instead to assess the withstand capacity of the inter-turn insulation of the reactor. However, this method has a relatively short action time and low energy. It is difficult to distinguish, and the change of electrical parameters caused by inter-turn short circuit is small, and it is also difficult to distinguish from the lightning impulse waveform.

There is also a high-frequency pulse oscillation method. The research of this method is based on the reactor parameter change phenomenon when the inter-turn insulation breaks down and short-circuits. A high-frequency voltage is applied to the reactor, and the normal reactor and the fault reactor are compared. The applied voltage presents different attenuation constants, so as to judge the inter-turn insulation state of the reactor. This method is only effective for reactors with inter-turn insulation defects, but for reactors with inter-turn insulation hazards but no insulation breakdown. The device cannot realize the detection function. A dry-type air-core reactor turn-to-turn insulation testing device with a publication number of CN105445630 includes an input module, a dry-type air-core reactor, a monitoring circuit, an MCU system, an overcurrent protection circuit, a bus module, a display module, a signal conversion switch, a digital / conversion circuit, input operation module; monitoring circuit includes voltage monitoring circuit, reactive current monitoring circuit, active current monitoring circuit, power factor monitoring circuit, input module includes voltage regulator, high voltage pulse circuit, high frequency oscillation circuit, dry hollow The input end of the reactor is connected to a high-frequency oscillation circuit, and the output end is connected to a reactive current monitoring circuit, an active current monitoring circuit, and a power factor monitoring circuit.

Therefore, it is more and more important to conduct experimental research on the inter-turn insulation of dry-type air-core reactors under different operating conditions, and to realize on-site detection of inter-turn insulation of dry-type air-core reactors.

Utility model content

In view of this, the purpose of this utility model is to provide a dry-type air-core reactor turn-to-turn insulation performance test system for the deficiencies of the prior art, which can conduct induction withstand voltage tests on 35 kV dry-type air-core reactors on site, and complete On-site boosting operation of the reactor.

In order to solve the problems of the technologies described above, the technical scheme adopted by the utility model is as follows:

A dry-type air-core reactor turn-to-turn insulation performance test system, which includes a high-voltage switchgear, a frequency conversion test power supply, a test transformer, a reactive power compensation unit, a partial discharge monitoring unit, and a unit under test. The high-voltage switchgear is connected to Input 380V three-phase AC current, the high-voltage switchgear, frequency conversion test power supply, test transformer, reactive power compensation unit, partial discharge monitoring unit, and the unit under test are connected in sequence; the partial discharge monitoring unit includes coupling capacitors, measuring impedance and a partial discharge tester, the unit under test includes a dry-type air-core reactor and an AC voltage measurement unit, and the dry-type air-core reactor and the AC voltage measurement unit are connected in parallel.

Preferably, an ammeter is connected in series in the high-voltage circuit of the test transformer.

Preferably, the reactive power compensation unit adopts an oil-immersed dense compensation capacitor bank.

Preferably, the reactive power compensation unit is composed of multiple capacitor banks connected in series, and the capacitor bank is composed of multiple capacitors connected in parallel.

Preferably, the test transformer is an excitation transformer.

The beneficial effects of the utility model are:

1) The utility model can carry out the induction withstand voltage test on the dry-type air-core reactor on site, and complete the on-site assessment of the inter-turn insulation of the reactor;

2) The rated voltage of the step-up test transformer required by the utility model is low, which reduces the manufacturing difficulty of the test transformer;

3) The utility model has its own partial discharge monitoring unit, which can measure the partial discharge during the test.

4) The utility model has its own reactive power compensation capacitor, and the required active power supply capacity is small, which can meet the requirements of field tests.

5) The method of the utility model is clear, which breaks through the bottleneck that the traditional dry-type air-core reactor cannot perform effective inter-turn insulation on site, and makes it possible to conduct induction withstand voltage of the dry-type air-core reactor on site, and at the same time, it is possible to detect partial discharge during the test process. The level of measurement is monitored, which fills the gap in the domestic on-site assessment of the inter-turn insulation performance of dry-type air-core reactors, and effectively ensures the safe operation of dry-type air-core reactors.

Description of drawings

Fig. 1 is a functional block diagram of the inter-turn insulation performance test system of the utility model dry-type air-core reactor.

Fig. 2 is a schematic circuit diagram of the partial discharge monitoring unit of the dry-type air-core reactor turn-to-turn insulation performance test system of the utility model.

detailed description

Below in conjunction with accompanying drawing, the technical scheme of the utility model is further described:

Example 1:

As shown in Figure 1, the utility model includes a high-voltage switchgear 1, a frequency conversion test power supply 2, an excitation transformer 3, a reactive power compensation unit 4, a partial discharge monitoring unit 5, and a tested product unit 6. The high-voltage switchgear 1 is connected to 380V Three-phase AC current, high-voltage switchgear 1, frequency conversion test power supply 2 and excitation transformer 3 are electrically connected in sequence, and excitation transformer 3 boosts the output voltage U ₁ of frequency conversion test power supply 2 to U ₂ , and an ammeter is connected in series in the high voltage circuit of excitation transformer 3 . The partial discharge monitoring unit 5 is composed of a coupling capacitor C _K , a detection impedance Z _M and a partial discharge tester M. The reactive power compensation unit 4 is composed of three identical capacitor banks C1-C3, among which, the capacitor banks C1-C3 are formed by three capacitors connected in parallel, and these three capacitor banks are connected in parallel to increase the capacity of reactive power compensation . The unit under test 6 includes a dry-type air-core reactor and an AC voltage measurement unit, and the dry-type air-core reactor and the AC voltage measurement unit are connected in parallel.

The test transformer excites the resonant circuit, and the reactive power compensation unit in the circuit and the unit under test produce parallel resonance through the frequency conversion of the output frequency of the test power supply. The excitation transformer 3 excites the resonant circuit, and the reactive power compensation unit 4 in the circuit and the unit under test 6 generate parallel resonance through the output frequency of the test power supply 2 to realize the complete compensation of reactive power. The high-voltage switchgear 1 protects the excitation transformer 3 and prevents equipment from being damaged by excessive current. The partial discharge monitoring unit 5 monitors and evaluates the partial discharge level of the entire pressurized system by using the principle of the pulse current method through the coupling capacitor C _K , the detection impedance Z _M and the partial discharge tester M.

The utility model raises the output voltage of the frequency conversion test power supply 2 to a suitable voltage value through the excitation transformer 3 during the test, so as to excite the whole test circuit, and dynamically adjust the output frequency of the frequency conversion test power supply 2 and the capacitor bank of the reactive power compensation unit 4 Switch the number of groups, so that the reactive power compensation unit and the reactor under test can achieve parallel resonance within the frequency range of the variable frequency test power supply (30Hz-300Hz), thereby realizing complete compensation of reactive power. At this time, the output frequency of the variable frequency test power supply 2 It is the test frequency, and the voltage applied to the tested product 6 is the resonance voltage. According to the principle of parallel resonance, the test system uses high-voltage reactors and compensation capacitors to resonate to generate high voltage and high current. The power supply only needs to provide the part of active power consumption in the system, and the required power supply capacity is greatly reduced. The volume and weight of the experimental equipment also significantly reduced. And the partial discharge monitoring unit of the pulse current method is introduced into the test system, so as to realize the detection and assessment of the partial discharge level of the whole test circuit, especially the tested product 6.

Example 2:

As shown in Figure 2, since the utility model uses the pulse current method to monitor the partial discharge in the partial discharge monitoring unit 5, it is necessary to perform partial discharge (partial discharge) on the entire test system before the pressurization test starts. The calibration of the whole test circuit is calibrated by using a standard capacitor and a square wave generator. One end of the output of the square wave generator is grounded, and the other end uses the signal line to output a square wave signal, which is applied to the first end of the coupling capacitor, with 500pC as the For example, adjust the square wave output at this time so that the output is 500pC, and at the same time, the square wave signal should be read out on the partial discharge detector, and the square wave calibration can be performed according to the instructions of the partial discharge detector.

The method of the utility model is clear, which breaks through the bottleneck that the traditional dry-type air-core reactor cannot perform effective inter-turn insulation on site, and makes it possible to conduct induction withstand voltage of the dry-type air-core reactor on site, and at the same time, the level of partial discharge during the test process The monitoring has filled the gap in the domestic on-site assessment of the inter-turn insulation performance of dry-type air-core reactors, and has effectively ensured the safe operation of dry-type air-core reactors.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model without limitation, other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solution of the utility model, as long as they do not depart from the technical solution of the utility model The spirit and scope should be included in the claims of the present utility model.

Claims (5)

1. A dry-type air-core reactor turn-to-turn insulation performance test system is characterized in that: it comprises a high-voltage switchgear, a frequency conversion test power supply, a test transformer, a reactive power compensation unit, a partial discharge monitoring unit and a tested product unit. The high-voltage switchgear is connected to 380V three-phase AC current, and the high-voltage switchgear, frequency conversion test power supply, test transformer, reactive power compensation unit, partial discharge monitoring unit, and tested unit are connected in sequence; the partial discharge monitoring unit includes a coupling Capacitance, measuring impedance and partial discharge tester, the unit under test includes a dry-type air-core reactor and an AC voltage measurement unit, and the dry-type air-core reactor and the AC voltage measurement unit are connected in parallel. 2. A dry-type air-core reactor turn-to-turn insulation performance test system according to claim 1, characterized in that: an ammeter is connected in series in the high-voltage circuit of the test transformer. 3. A dry-type air-core reactor turn-to-turn insulation performance test system according to claim 1, characterized in that: said reactive power compensation unit adopts an oil-immersed intensive compensation capacitor bank. 4. A dry-type air-core reactor turn-to-turn insulation performance test system as claimed in claim 1, characterized in that: the reactive power compensation unit is composed of a plurality of capacitor banks connected in series, and the capacitor bank is composed of multiple capacitors connected in parallel. 5. A dry-type air-core reactor turn-to-turn insulation performance test system according to claim 1, characterized in that: the test transformer is an excitation transformer.