CN205992025U - A kind of 220KV and above capacitance type potential transformer test circuit - Google Patents

Abstract

The utility model discloses a kind of 220KV and above capacitance type potential transformer test circuit, including：Testing capacitance formula voltage transformer and test pontic circuit, described testing capacitance formula voltage transformer includes the first main capacitance, second section main capacitance, first segment derided capacitors and intermediate transformer, described test pontic circuit includes High voltage output interface and test line interface, the negative pole end of described second section main capacitance is connected ground connection with upper end lead, the positive terminal of second section main capacitance is connected with the positive terminal of first segment main capacitance, the negative pole end of first segment main capacitance is connected with the positive terminal of first segment derided capacitors, the negative pole end of first segment derided capacitors is derided capacitors tail end, the negative pole end of first segment main capacitance is connected with the former limit head end of intermediate transformer, intermediate transformer first winding tail end and derided capacitors tail end are passed through permutator and are connected with test line interface, the positive terminal of described second section main capacitance is connected with High voltage output interface by high pressure heart yearn.

Description

A 220KV and above capacitive voltage transformer test circuit

technical field

The utility model relates to the technical field of power system detection, in particular to a test circuit for a 220KV and above capacitive voltage transformer, especially suitable for the pre-test of a 220KV and above capacitive voltage transformer (CVT) without removing the high-voltage lead wire Accurately and quickly complete the dielectric loss capacitance test of CVT.

Background technique

When the power equipment is in operation, it is necessary to conduct regular power outage inspections to detect the operating conditions of the equipment, grasp its health status, and ensure the safe and stable operation of the power equipment. When carrying out the preventive test work of 220kV and above capacitor voltage transformer (CVT), the conventional experimental device needs to remove the high-voltage lead wire once during the experiment to carry out the test, but the current 220 kV and above voltage transformer removes the high-voltage The lead wire needs to use high-altitude vehicles, which is time-consuming and laborious, and the on-site power outage time is often short, the time is tight, and the task is heavy, which increases the work intensity of the test personnel; The induced voltage increases the safety risk of on-site test personnel; during routine test wiring, there is a high induced voltage on the test wire, which increases the error of the test data and causes damage to the test instrument; when the high-voltage lead is removed on site, the staff often It is necessary to stand on the porcelain bottle of the capacitive voltage transformer, which increases the risk of damage to the porcelain bottle by external force and adversely affects the complete operation and maintenance of the power grid.

Utility model content

The technical problem to be solved by the utility model is to provide a 220KV and above capacitive voltage transformer test circuit for the above-mentioned deficiencies in the prior art, especially suitable for 220kV and above capacitive voltage transformer (CVT) pre-test, Accurately and quickly complete the dielectric loss capacitance test of CVT without removing the high-voltage lead wires, which can effectively shorten the time for equipment power failure pre-test, improve work efficiency, reduce the work intensity of testers, and greatly reduce the safety hazards of testers.

The technical scheme that the utility model solves its technical problem adopts is:

A 220KV and above capacitive voltage transformer test circuit, comprising: a capacitive voltage transformer to be tested and a test bridge circuit, the capacitive voltage transformer to be tested includes a first main capacitor, a second main capacitor, a second A voltage dividing capacitor and an intermediate transformer, the test bridge circuit includes a high voltage output interface and a test line interface, the negative end of the second main capacitor is connected to the upper lead wire to ground, the positive end of the second main capacitor is connected to the The positive terminal of the first section of the main capacitor is connected, the negative terminal of the first section of the main capacitor is connected to the positive terminal of the first section of the voltage dividing capacitor, the negative terminal of the first section of the voltage dividing capacitor is the end of the voltage dividing capacitor, the first section of the main capacitor The negative end of the main capacitor is connected to the primary end of the intermediate transformer, the end of the primary winding of the intermediate transformer and the end of the voltage dividing capacitor are connected to the interface of the test line through the transfer switch, and the positive end of the second section of the main capacitor is connected to the high voltage through the high voltage core wire. output interface connection.

Further, the transfer switch includes a first switch, a second switch, and a third switch, the first switch is connected to the negative terminal of the first voltage dividing capacitor, and the second switch is connected to the primary winding end of the intermediate transformer. The terminal is connected, and the third switch is grounded.

Further, the intermediate transformer is composed of a primary winding, a secondary winding and a remaining winding, wherein the first end of the primary winding is connected to the positive terminal of the second main capacitor, the tail end of the primary winding is connected to the test line interface through a transfer switch, and the remaining A damping resistor is connected in parallel between the head end of the winding and the tail end of the remaining winding.

Further, the end of the primary winding of the intermediate transformer is connected to a compensating reactor.

Compared with the prior art, the utility model has the following advantages:

The utility model flexibly applies the conventional M-type test method to the test work of the CVT. The new test method does not need to remove the high-voltage lead wire, shortens the power failure time of the equipment, and greatly reduces the work intensity of the field test personnel; Risk of electric shock; ensures the accuracy of the test data, and avoids the damage of the test equipment by induced electricity; reduces the risk of damage to the porcelain bottle by external force, and ensures the complete and stable operation of the power grid.

Description of drawings

Fig. 1 is a kind of 220KV and above capacitive voltage transformer test circuit structural diagram provided by the utility model;

Fig. 2 is the structural diagram of the transfer switch provided by the utility model;

Fig. 3 is an equivalent circuit diagram of a 220KV and above capacitive voltage transformer test circuit provided by the utility model.

detailed description

Describe the specific implementation of the utility model below in conjunction with accompanying drawing and embodiment:

Referring to Fig. 1～Fig. 3, among them Fig. 1 is a kind of 220KV and above capacitive voltage transformer test circuit structural diagram provided by the utility model; Fig. 2 is the said transfer switch structural diagram provided by the utility model; Fig. 3 is this utility model The utility model provides an equivalent circuit diagram of a 220KV and above capacitive voltage transformer test circuit.

As shown in Figures 1 to 3, a 220KV and above capacitive voltage transformer test circuit includes: a capacitive voltage transformer to be tested and a test bridge circuit, and the capacitive voltage transformer to be tested includes a first main Capacitor C ₁₁ , the second-section main capacitor C ₁₂ , the first-section voltage dividing capacitor C ₂ and the intermediate transformer T, the test bridge circuit includes a high-voltage output interface and a test line interface, and the second-section main capacitor C ₁₂ The negative terminal is connected to the upper lead wire to ground, the positive terminal of the second main capacitor C ₁₂ is connected to the positive terminal of the first main capacitor C ₁₁ , the negative terminal of the first main capacitor C ₁₁ is connected to the first voltage dividing capacitor C ₂ The positive end of the first section of the voltage dividing capacitor C ₂ is connected to the end of the voltage dividing capacitor δ, the negative end of the first section of the main capacitor C ₁₁ is connected to the primary end of the intermediate transformer, and the end of the primary winding of the intermediate transformer T The terminal and the tail end of the voltage dividing capacitor are connected to the test line interface through the switch K, and the positive terminal _of the second main capacitor C12 is connected to the high voltage output interface through the high voltage core wire.

Further, the transfer switch includes a first switch K1, a second switch K2, and a third switch K3, the first switch K1 is connected to the negative terminal of the first voltage dividing capacitor, the second switch K2 is connected to the The tail end of the primary winding of the intermediate transformer T is connected, and the third switch K3 is grounded.

Further, the intermediate transformer T is composed of a primary winding, a secondary winding and a remaining winding, wherein the first end 1a of the primary winding is connected to the positive end _of the second main capacitor C12, and the tail end X of the primary winding is connected to The test line interface is connected, and the damping resistance Z is connected in parallel between the first end da of the remaining winding and the tail end dn of the remaining winding.

Further, the end X of the primary winding of the intermediate transformer T is connected with a compensating reactor L. A protection gap F is formed between the intermediate transformer and the test line interface by setting the compensating reactor.

In the embodiment of the present invention, for the test of the 220KV capacitive voltage transformer, the dielectric loss capacitance of each capacitor of the capacitive voltage transformer to be tested needs to be tested separately on site. Before the test, the sample should be fully discharged to ensure the safety of the test personnel. During the test, the first voltage dividing capacitor δ of the electromagnetic unit and the grounding of the tail end X of the primary winding must be opened. Connect the negative terminal of the first voltage dividing capacitor to the tail end of the primary winding with short wires and connect to the C _x test line. The high-voltage core wire H _V is connected to the positive terminal of the second main capacitor. The loss capacity is tested. The test wiring adopts the M-type wiring method, and the test voltage is 10kV.

When testing the dielectric loss capacitance of the first main capacitor C ₁₁ and the first voltage dividing capacitor C ₂ , the test can be completed by using the conventional self-excitation method. During the test, the negative terminal δ of the first voltage dividing capacitor C ₂ is grounded After opening, connect the C _x test line, the high-voltage core line H _V line is connected to the upper end of the first main capacitor C ₁₁ , the tail end X of the intermediate transformer is normally grounded, and the self-excitation method output end of the dielectric loss tester is respectively connected to the remaining winding of the intermediate transformer ends. Due to the limited insulation level of the negative terminal δ of the voltage dividing capacitor _C2 in the first section, the test voltage should not be too high, and the general laboratory adopts 2kV.

The purpose of the utility model is to safely, efficiently and accurately complete the testing work of 220kV and above capacitive voltage transformers without dismantling the high-voltage lead wires, so as to improve the working efficiency.

M-type wiring combines two wiring methods: reverse wiring and forward wiring: the upper half branch of M-type wiring can be regarded as a reverse wiring, and the lower half branch can be equivalently regarded as a positive wiring branch. The total current is I _total , which can be directly measured by the instrument, the lower half of the branch current is I _positive , and I _positive can be directly measured by the C _x test line, and the upper half of the branch current is I _reverse , and the branch current method I _reverse = I _Total - I _Positive . According to the following formula:

Among them, I reverse is the reverse wiring current; I positive is the positive terminal current, I always is the total test current; UN is the test voltage; C2 is the second voltage dividing capacitor.

It can be seen from formulas 1.1 and 1.2 that the M-type connection can accurately test the dielectric loss capacitance of the upper and lower capacitors.

The M-type wiring in the embodiment of the utility model is used to test the 220 kV capacitive voltage transformer of a certain substation on site, and the test data is compared with the positive wiring measurement by removing the lead wire;

Test results of 220kV I-bus voltage transformer in a 750kV substation:

By analyzing the above table, it can be seen that the capacitance of the capacitance tested by the M-type wiring is compared with the factory value <0.438, and the capacitance of the capacitance tested by the M-type wiring is compared with the positive connection of the disconnection by <0.132. Comprehensive test data analysis The M-type wiring fully meets the accuracy requirements of the test data, and the M-type wiring does not need to remove the lead wire once, which greatly facilitates on-site testing and is the preferred method for on-site testing.

The utility model flexibly applies the conventional M-type test wiring to the test work of the CVT. The new test method does not need to dismantle the high-voltage lead wire, shortens the power outage time of the equipment, and greatly reduces the work intensity of the field test personnel; Risk of electric shock; ensures the accuracy of the test data, and avoids the damage of the test equipment by induced electricity; reduces the risk of damage to the porcelain bottle by external force, and ensures the complete and stable operation of the power grid.

The preferred embodiment of the utility model has been described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned embodiment. Make various changes.

Many other changes and modifications can be made without departing from the spirit and scope of the present invention. It should be understood that the invention is not limited to specific embodiments, and the scope of the invention is defined by the appended claims.

Claims (4)

1. a kind of 220KV and above capacitance type potential transformer test circuit, including：Testing capacitance formula voltage transformer and test Pontic circuit, described testing capacitance formula voltage transformer include the first main capacitance, second section main capacitance, first segment derided capacitors and Intermediate transformer, described test pontic circuit includes High voltage output interface and test line interface, described second section main capacitance negative Extremely it is connected ground connection with upper end lead, the positive terminal of second section main capacitance is connected with the positive terminal of first segment main capacitance, first segment The negative pole end of main capacitance is connected with the positive terminal of first segment derided capacitors, and the negative pole end of first segment derided capacitors is derided capacitors tail End, the negative pole end of first segment main capacitance is connected with the former limit head end of intermediate transformer, intermediate transformer first winding tail end with divide Voltage capacitance tail end is passed through permutator and is connected with test line interface, the positive terminal of described second section main capacitance by high pressure heart yearn and High voltage output interface connects.

2. a kind of 220KV according to claim 1 and above capacitance type potential transformer test circuit it is characterised in that Described permutator includes first switch, second switch and the 3rd switch, the negative pole of described first switch and the first derided capacitors End connects, and described second switch is connected with described intermediate transformer first winding tail end, described 3rd switch ground connection.

3. a kind of 220KV according to claim 1 and above capacitance type potential transformer test circuit it is characterised in that Described intermediate transformer is made up of first winding, Secondary Winding and remaining winding, wherein the head end of first winding and second section master The positive terminal of electric capacity connects, and first winding tail end is passed through permutator and is connected with test line interface, remaining winding head end and residue Damping resistance in parallel between the tail end of winding.

4. a kind of 220KV according to claim 3 and above capacitance type potential transformer test circuit it is characterised in that The first winding tail end of described intermediate transformer connects compensation reactor.