WO2023077533A1

WO2023077533A1 - Resistance measurement method suitable for circuit breaker or isolating switch under high electric field intensity

Info

Publication number: WO2023077533A1
Application number: PCT/CN2021/129631
Authority: WO
Inventors: 张军; 马荣华; 赵凯; 薛天水; 王永顺
Original assignee: 华能国际电力股份有限公司德州电厂
Priority date: 2021-11-03
Filing date: 2021-11-09
Publication date: 2023-05-11
Also published as: CN114019245A

Abstract

The present invention provides a resistance measurement method suitable for a circuit breaker or isolating switch under high electric field intensity. A first end of a circuit breaker or isolating switch to be tested is connected to a first ground switch, and a second end of said circuit breaker or isolating switch is connected to a second ground switch. The method comprises the steps of: connecting a first ground resistor to the first end of said circuit breaker or isolating switch, the resistance value of the first ground resistor meeting a set condition; connecting a second ground resistor to the second end of said circuit breaker or isolating switch, the resistance value of the second ground resistor meeting the set condition; respectively connecting leads for testing to the two ends of said circuit breaker or isolating switch; correspondingly connecting the leads for testing to resistance test instruments; and disconnecting the first ground switch and the second ground switch, and obtaining the resistance value of said circuit breaker or isolating switch by using the resistance test instruments. The present invention is used for solving the problem of low safety in the resistance measurement process of the circuit breaker or isolating switch caused by high induced voltage under the existing high-voltage condition.

Description

Resistance measurement method for circuit breakers or disconnectors under high electric field strength

technical field

The invention relates to the field of circuit breakers or isolating switches, in particular to a resistance measurement method suitable for circuit breakers or isolating switches under high electric field intensity.

Background technique

During the operation of the power system, in order to safely and effectively transmit electric energy from the power plant to the user terminal, it needs to go through step-up, step-down and other processing in the middle. In this process, circuit breakers and disconnectors play an important role. Among them, the main function of the circuit breaker is: during normal operation, it is used to switch the operation mode, so that the equipment or line is connected to the circuit or withdrawn from operation, so as to play a control role; when the equipment or line fails, it can quickly cut off the fault circuit , Protect the normal operation of the non-faulty part, and play a protective role. The biggest feature is that it can disconnect the load current and short-circuit current in the circuit, and has the ability to extinguish the arc. The main functions of the isolating switch include: 1) Isolating voltage: When overhauling electrical equipment, use the isolating switch to isolate the overhauled equipment from the power supply voltage; 2) Switching operation: When putting into the standby bus or bypass bus and changing the operation mode, Cooperate with the circuit breaker and cooperate to complete; 3) Opening and closing small current: the disconnector without arc extinguishing device can not be used to connect the load current and cut off the roadblock current, but it has the opening and closing small inductive current (not more than 2A) and capacitance Current (not greater than 5A) capability.

In order to test the performance of circuit breakers and isolating switches, it is necessary to measure the resistance of the conductive loop on the contacts of circuit breakers and isolating switches and their electrical connections. When performing measurement work, it needs to be carried out when the circuit breaker or isolating switch is powered off, because other equipment (such as busbars, lightning arresters, voltage transformers, current transformers, other isolating switches and circuit breakers, etc.) are still operating under high voltage , the measured circuit breaker and isolating switch will induce a higher voltage, generally thousands of volts or even tens of thousands of volts of induced high voltage, the specific value is determined by the measured circuit breaker and isolating switch circuit and the live equipment and the ground Determined by the parasitic capacitance of the space distance between them and the voltage level of the charged equipment, this induced voltage has a greater impact on testers and test equipment. And during the measurement process, it is necessary to frequently connect or replace the relevant lead wires, and the existence of the above-mentioned high induced voltage makes this process a great potential safety hazard.

Contents of the invention

In view of the above shortcomings of the prior art, the present invention provides a resistance measurement method suitable for circuit breakers or disconnectors under high electric field strength, to improve the resistance measurement of circuit breakers or disconnectors due to high induced voltages under existing high voltage conditions The problem of low process safety.

In order to achieve the above object and other related objects, the present invention provides a resistance measurement method suitable for circuit breakers or isolating switches under high electric field strength. The first end of the circuit breaker or isolating switch to be tested is connected to the first grounding switch. The second end of the circuit breaker or isolating switch to be tested is connected to the second grounding switch, including the step of: connecting the first end of the circuit breaker or isolating switch to be tested with a first grounding resistance, the resistance of the first grounding resistance conforms to the set Set the conditions; connect the second grounding resistor to the second end of the circuit breaker or isolating switch to be tested, and the resistance value of the second grounding resistor meets the set conditions; connect the two ends of the circuit breaker or isolating switch lead wires; connect the test lead wires to a resistance testing instrument correspondingly; disconnect the first grounding switch and the second grounding switch, and use the resistance testing instrument to obtain the resistance value of the circuit breaker or isolating switch to be tested.

In an embodiment of the present invention, the setting condition is: the range of the resistance R is 20Ω≤R≤200Ω.

In one embodiment of the present invention, the resistance of the first grounding resistor is the same as that of the second grounding resistor.

In one embodiment of the present invention, the resistance of the first grounding resistor is 100 ohms.

In one embodiment of the present invention, the first grounding switch is connected in parallel with the first grounding resistor; the second grounding switch is connected in parallel with the second grounding resistor.

In one embodiment of the present invention, the test leads include voltage leads and current leads.

In one embodiment of the present invention, the step of obtaining the resistance value of the circuit breaker or isolating switch to be tested by using a resistance testing instrument includes: grounding the casing of the resistance testing instrument, and then turning on the power of the tester to obtain the resistance value of the circuit breaker to be tested. resistor or disconnect switch.

In one embodiment of the present invention, the step of connecting the test lead wires at both ends of the circuit breaker or isolating switch to be tested includes: connecting the test lead wires to the circuit breaker or isolator to be tested with a special test clamp. both ends.

In one embodiment of the present invention, before the step of connecting one end of the circuit breaker or isolating switch to be tested to the first grounding resistor, it further includes: detecting whether the operator complies with the safe operation standard.

In one embodiment of the present invention, after the step of obtaining the resistance value of the circuit breaker or isolating switch to be tested by using a resistance testing instrument, it further includes: closing the first grounding switch and the second grounding switch, removing the first grounding resistor 1. For the second grounding resistance, remove the test lead wires at both ends of the circuit breaker or isolating switch to be tested, and remove the test lead wires on the resistance testing instrument.

The invention is applicable to the resistance measurement method of the circuit breaker or isolating switch under high electric field intensity. The first grounding resistance or the second grounding resistance eliminates the induced voltage of the conductive circuit of the belt measuring circuit breaker or isolating switch, so that it can be carried out without closing the grounding switch. The connection or replacement of relevant wires reduces potential safety hazards and ensures the safety of staff; at the same time, it avoids damage to the test equipment due to the impact of induced voltage; Comply with the set conditions to ensure the accuracy of the measurement results.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the flow chart of the resistance measuring method that is applicable to circuit breaker or isolating switch under the high electric field intensity described in the present invention;

Figure 2 is a circuit connection diagram of the circuit breaker and isolating switch of the 500KV step-up station;

Fig. 3 is a working principle diagram of the resistance measuring method suitable for circuit breakers or isolating switches under high electric field strength according to the present invention.

Label description

100. Circuit breaker or isolating switch to be tested; 200. First grounding resistance; 300. Second grounding resistance; 400. Test lead; 401. Voltage lead; 402. Current lead; 500. Resistance testing instrument.

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the case of no conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementations, not for limiting the protection scope of the present invention. The test methods for which specific conditions are not indicated in the following examples are usually in accordance with conventional conditions, or in accordance with the conditions suggested by each manufacturer.

It should be noted that terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable scope of the invention and the change or adjustment of its relative relationship shall also be regarded as the practicable scope of the present invention without any substantial change in the technical content.

Please refer to Fig. 1 and Fig. 3, the present invention provides a kind of resistance measuring method that is applicable to circuit breaker or isolating switch under high electric field intensity, is used for measuring the contact resistance of circuit breaker or isolating switch conductive circuit under electric field intensity, described to-be-tested The first end of the circuit breaker or isolating switch 100 is connected to the first grounding switch, and the second end of the circuit breaker or isolating switch 100 to be tested is connected to the second grounding switch. The method includes the steps of: The first end of 100 is connected to the first grounding resistor 200, and the resistance value of the first grounding resistor 200 meets the set conditions; the second end of the circuit breaker or isolating switch 100 to be tested is connected to the second grounding resistor 300, and the first The resistance value of two grounding resistors 300 meets the setting conditions; connect the test lead 400 respectively at the two ends of the circuit breaker to be tested or the isolating switch 100; the corresponding test lead 400 is connected to the resistance testing instrument 500; disconnect For the first grounding switch and the second grounding switch, use the resistance testing instrument 500 to obtain the resistance value of the circuit breaker or isolating switch 100 to be tested.

The high electric field intensity is the electric field intensity radiated when the voltage of the relevant equipment is greater than or equal to 110KV, and the relevant equipment is the equipment capable of radiating electric field in the environment where the circuit breaker or disconnector 100 to be tested is located, such as a booster station Intermediate busbars, lightning arresters, voltage transformers, current transformers, other isolating switches and circuit breakers, etc.

The first grounding switch 200 and the second grounding switch 300 can effectively eliminate the induced voltage on the circuit breaker or isolating switch 100 to be measured. The setting condition is that the resistance value is much greater than the resistance value of the circuit breaker or the isolating switch 100 to be tested, and the much greater value may be that the resistance value is greater than or equal to 1000 times. For example, in one embodiment of the present invention, the setting condition is: the range of the resistance R is 20Ω≤R≤200Ω. The magnitude of circuit breaker circuit resistance is micro-ohms (generally about 80 micro-ohms), the magnitude of isolating switch circuit resistance is milliohms (generally about 300 milliohms), and the range of resistance R is 20 ohms≤R≤200 ohms Much greater than the loop resistance of the circuit breaker or disconnect switch.

In one embodiment of the present invention, the resistance of the first grounding resistor is the same as that of the second grounding resistor. The resistance values of the two grounding resistors are consistent, and there is no need to distinguish the two ends during the connection process, which increases the convenience of the connection process and improves the detection efficiency. For example, the resistance of the first grounding resistor is 100Ω.

In one embodiment of the present invention, the first grounding switch is connected in parallel with the first grounding resistor; the second grounding switch is connected in parallel with the second grounding resistor. The first grounding switch is connected in parallel with the first grounding resistor, so that the safety of operators or measuring instruments can be ensured without closing the first grounding switch when connecting or replacing related lines. The second grounding switch is connected in parallel with the second grounding resistance, so that the safety of operators or measuring instruments can be ensured without closing the second grounding switch when connecting or replacing related lines.

In one embodiment of the present invention, the test lead 400 includes a voltage lead 401 and a current lead 402 . Two ends of the circuit breaker or isolating switch to be tested are respectively connected with a voltage lead and a current lead, and the other end of each voltage lead or current lead is correspondingly connected to the interface on the resistance testing instrument 500 .

In one embodiment of the present invention, the step of obtaining the resistance value of the circuit breaker or isolating switch to be tested by using a resistance testing instrument includes: grounding the casing of the resistance testing instrument, then turning on the power of the tester, and obtaining the resistance value of the circuit breaker to be tested resistor or disconnect switch.

In one embodiment of the present invention, the step of connecting the test lead wires at both ends of the circuit breaker or isolating switch to be tested includes: connecting the test lead wires to the circuit breaker or isolator to be tested with a special test clamp. both ends. The special test clamps can be alligator clips.

In one embodiment of the present invention, before the step of connecting one end of the circuit breaker or isolating switch to be tested to the first grounding resistor, it also includes: detecting whether the operator complies with the safe operation standard, and only under the condition of meeting the safe operation standard can he enter the next step. one step. The operator can be a staff member, or an intelligent operation device or robot. When the operator is a worker, the corresponding safety operation standard is: confirm that the equipment has been powered off and take safety measures. The operator should wear insulating shoes and gloves, keep a sufficient safe distance from other operating equipment, and be supervised by a special person. . In one embodiment of the present invention, before the step of detecting whether the operator complies with the safety operation standard, processing a work ticket is also included to obtain the operation authority.

In an embodiment of the present invention, the first grounding resistor 200 or the second grounding resistor 300 can be a wire whose resistance meets a set condition, or an independent resistor with certain mechanical strength and sufficient heat capacity. The first grounding resistor 200, the second grounding resistor 300 and the test lead wire 400 should be protected by an insulating sheath, the lead wire should have sufficient cross-sectional area and mechanical strength, and the material of the lead wire should be multi-strand copper wire.

Specifically, taking a 500KV step-up station as an example, please refer to Figure 2 to measure the resistance of the conductive loop of the 5023 circuit breaker. The test method is as follows:

1) Apply for a work ticket, confirm that the equipment has been powered off and take safety measures.

2) The staff should wear insulating shoes and gloves, keep a sufficient safe distance from other operating equipment, and be supervised by special personnel.

3) Close the 5023 circuit breaker, and connect a resistor (R1/R2, generally 100) at the 502317/502327 grounding switch at both ends of the conductive circuit of the 5023 circuit breaker to be measured. ohms) to ground, and at the same time clamp the voltage and current leads of the conductive circuit contact resistance test instrument to both ends of the conductive circuit of the 5023 circuit breaker with special test clamps; the far greater than can be greater than or equal to 1000 times the resistance.

4) Connect the voltage lead and current lead to the loop resistance tester, and then pull the 502317/502327 grounding switch.

5) The shell of the loop resistance testing instrument should be reliably grounded, and the loop resistance test should be performed by connecting the power supply of the testing instrument.

6) After the test, close the 502317/502327 grounding switch, remove and connect the resistors (R1/R2) at both ends of the conductive circuit of the circuit breaker to be measured, and remove the voltage and current leads of the conductive circuit contact resistance tester at the same time , test voltage current leads.

7) The test is complete.

The method of testing the contact resistance of the conductive circuit of the 50231 isolating switch is as follows:

3) Close the 50231 isolating switch, and connect a resistor with a resistance value greater than 1000 times the resistance of the conducting circuit of the 5023 circuit breaker at the 502317/5023617 grounding switch at both ends of the conductive circuit of the 50231 isolating switch (R2/R3, generally 100 ohms Left and right) grounded, and at the same time, clamp the voltage and current leads of the conductive circuit contact resistance test instrument to both ends of the conductive circuit of the 50231 isolating switch with special test clamps.

4) Connect the voltage lead and current lead to the loop resistance tester, and then pull the 502317 and 5023617 grounding switches.

6) After the test, close the 502317 and 5023617 grounding switches, remove and connect the resistors (R2/R3) at both ends of the conductive circuit of the circuit breaker to be measured, and remove the voltage and current of the conductive circuit contact resistance testing instrument at the same time. Leads, test voltage current leads.

7) The test is complete.

Please refer to Figure 3, Figure 3 shows the resistance measurement principle of the present invention, the first grounding resistance R _{ground 1} and the second grounding resistance R _{ground 2} are respectively grounded, so it can be regarded as the first ground resistance 200 and the second ground resistance 300 Connect in parallel to the two ends of the circuit breaker or isolating switch 100 to be tested from the ground terminal in series, and the resistance measured by the conductive loop is the total resistance:

Therefore, the present invention can guarantee the accuracy of the measurement result. In FIG. 3 , D1 and D2 are used to connect the voltage lead 401 , and C1 and C2 are used to connect the current lead 402 .

The invention is applicable to the resistance measurement method of the circuit breaker or isolating switch under high electric field intensity. The first grounding resistance or the second grounding resistance eliminates the induced voltage of the conductive circuit of the belt measuring circuit breaker or isolating switch, so that it can be carried out without closing the grounding switch. The connection or replacement of relevant wires reduces potential safety hazards and ensures the safety of staff; at the same time, it avoids damage to the test equipment due to the impact of induced voltage; Comply with the set conditions to ensure the accuracy of the measurement results. Therefore, the present invention effectively overcomes some practical problems in the prior art and thus has high utilization value and use significance.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims

A resistance measurement method suitable for circuit breakers or isolating switches under high electric field strength, the first end of the circuit breaker or isolating switch to be tested is connected to the first grounding switch, and the second end of the circuit breaker or isolating switch to be tested is Connecting a second grounding switch, characterized in that the method comprises the steps of:

A first grounding resistor is connected to the first end of the circuit breaker or isolating switch to be tested, and the resistance value of the first grounding resistor meets the set conditions;

A second grounding resistor is connected to the second end of the circuit breaker or isolating switch to be tested, and the resistance value of the second grounding resistor meets the set conditions;

Connect test lead wires to both ends of the circuit breaker or isolating switch to be tested;

Correspondingly connecting the test leads to the resistance testing instrument;

Turn off the first grounding switch and the second grounding switch, and use a resistance testing instrument to obtain the resistance value of the circuit breaker or isolating switch to be tested.
The resistance measurement method applicable to circuit breakers or disconnectors under high electric field strength according to claim 1, wherein the setting condition is: the range of resistance R is 20 ohms≤R≤200 ohms.
The resistance measuring method suitable for circuit breakers or disconnectors under high electric field strength according to claim 2, characterized in that the resistance value of the first grounding resistance is the same as that of the second grounding resistance.
The resistance measurement method suitable for circuit breakers or disconnectors under high electric field strength according to claim 3, characterized in that the resistance value of the first grounding resistor is 100 ohms.
The resistance measuring method suitable for circuit breakers or disconnectors under high electric field strength according to claim 1, wherein the first grounding switch is connected in parallel with the first grounding resistance; the second grounding switch is connected in parallel with the first grounding resistance; The second grounding resistor is connected in parallel.
The resistance measuring method applicable to circuit breaker or isolating switch under high electric field intensity according to claim 1, is characterized in that, described test lead comprises voltage lead and current lead.
The resistance measuring method applicable to circuit breakers or isolating switches under high electric field strength according to claim 1, wherein the step of obtaining the resistance value of the circuit breaker or isolating switch to be tested by using a resistance testing instrument comprises: The casing of the test instrument is grounded, and then the power of the test instrument is turned on to obtain the resistance value of the circuit breaker or isolating switch to be tested.
The resistance measuring method applicable to circuit breakers or isolating switches under high electric field strength according to claim 1, wherein the step of connecting test lead wires at both ends of the circuit breaker or isolating switch to be tested comprises: The special test clamp connects the test lead wires to both ends of the circuit breaker or isolating switch to be tested.
The resistance measuring method applicable to circuit breakers or isolating switches under high electric field strength according to claim 1, characterized in that, before the step of connecting one end of the circuit breaker or isolating switch to be tested to the first grounding resistor, it also includes: detection operation compliance with safe operating standards.
The resistance measuring method suitable for circuit breakers or isolating switches under high electric field strength according to claim 1, characterized in that, after the step of obtaining the resistance value of the circuit breaker or isolating switch to be tested by using a resistance testing instrument, it also includes: closing the Describe the first grounding switch and the second grounding switch, take off the first grounding resistor and the second grounding resistor, take off the test lead wires at both ends of the circuit breaker or isolating switch to be tested, and take off the test lead wires on the resistance testing instrument .