WO2021003774A1

WO2021003774A1 - Method for evaluating comprehensive performance of direct current high-speed switch

Info

Publication number: WO2021003774A1
Application number: PCT/CN2019/097616
Authority: WO
Inventors: 张长虹; 杨旭; 黎卫国; 黄忠康; 孙勇; 陈晓鹏
Original assignee: 中国南方电网有限责任公司超高压输电公司检修试验中心
Priority date: 2019-07-10
Filing date: 2019-07-25
Publication date: 2021-01-14
Also published as: CN110376514A; JP2022532577A; DE112019006961T5; CN110376514B; JP7201956B2

Abstract

A method for evaluating the comprehensive performance of a direct current high-speed switch, comprising: an internal arcing resistance performance detection test, used for determining whether the burning resistance performance of a tested circuit breaker meets requirements; an external insulation performance detection test, used for determining whether the insulation margin of the tested circuit breaker meets requirements; a direct current empty charge current breaking detection test, used for determining whether the breaking performance of the tested circuit breaker meets requirements; and a mechanical performance detection test, used for determining whether the mechanical reliability of the tested circuit breaker meets requirements; by means of four main detection tests including the internal arcing resistance performance detection test, the external insulation performance detection test, the direct current empty charge current breaking detection test, and the mechanical performance detection test, comprehensive performance detection can be performed for the HSS, in order to determine whether the performance requirements for use are met, and thereby ensuring the safety of use.

Description

Method for evaluating comprehensive performance of DC high-speed switches

Technical field

The invention relates to an evaluation method, in particular to a comprehensive performance evaluation method of a DC high-speed switch.

Background technique

DC high-speed switch (HSS) is mainly used in multi-terminal flexible DC transmission systems. The purpose of configuring the DC high-speed switch is to realize the on-line switching on and off of the third station of the DC system and the high-speed isolation of DC line faults, and to improve the reliability and availability of the entire DC system.

The DC high-speed switch generally adopts the open column circuit breaker type, and the operating mechanism can be hydraulic or spring. In order to coordinate the control of the multi-terminal system to realize the online input and withdrawal of the sending and receiving ends, the coordination requirements for the key performance parameters of the equipment are very high. Has the following characteristics:

(1) It should have an inherent long-term overload capacity (at the highest ambient temperature) of not less than 1.05p.u. system rated delivery capacity;

(2) Possess strong DC arcing tolerance;

(3) Have the ability to transfer the empty charging current of the DC line;

(4) It has a high opening speed, reliable mechanical action characteristics, and no refusal or misoperation.

The operating conditions of the DC high-speed switch mainly include four types: stable closing, opening transient process, stable opening and closing transient process. Under the 4 operating conditions encountered by HSS, the following capabilities are required:

1. In the HSS opening state, the converter stations on both sides of the fracture are unlocked, and the DC voltage on both sides reaches the rated DC voltage and is stable. At this time, the HSS can be reliably closed.

2. When the HSS is closed, the converter station on the side of the fracture is blocked, and the DC voltage on the blocking side remains unchanged at the beginning. The HSS should be able to open reliably. Due to the discharge of the pole line PT resistance, the voltage on the blocking side to ground gradually decreases. Therefore, the HSS should be able to withstand the gradually increasing terminal voltage before the high-speed switch supporting the knife is disconnected.

3. When the DC line fails, the HSS power measuring converter station quickly shifts the phase, and the HSS load-side converter station is quickly locked. Before the HSS opens, it needs to withstand an instantaneous large current of about 100ms with a magnitude of several Ten kA. The HSS opens after the current decays to zero.

4. Ability to withstand short-term internal arcing. For example, the Wudongde Rouzhi Project requires an internal arcing resistance of 3125A, 400ms, and 5 times. The Yungui Interconnection Project requires an internal arcing resistance of 3786A, 400ms, and 5 times. It is resistant, and the insulation jacket will not be damaged after five arcs.

5. HSS needs to have reliable high-speed closing and opening mechanical properties. For example, the Wudongde project requires closing time <100ms and opening time <30ms.

6. HSS does not need to have the capability of breaking DC current or fault current. However, the ability to break the residual current of the DC line is required, which is generally around 20A.

Therefore, before applying the HSS, it is necessary to conduct a test assessment and assessment of its overall key performance. However, there is currently no relevant test assessment method.

Summary of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a comprehensive performance evaluation method for DC high-speed switches, which is used to conduct a comprehensive test and assessment of the HSS before applying the HSS to evaluate whether its performance meets the specified requirements.

In order to achieve the above objective, the technical solution of the present invention is:

A comprehensive performance evaluation method for DC high-speed switches, including:

Internal arcing tolerance performance testing test, used to detect and judge whether the burning tolerance performance of the tested circuit breaker meets the requirements;

External insulation performance inspection test to detect whether the insulation margin of the tested circuit breaker meets the requirements;

DC no-charge current breaking detection test, used to detect and judge whether the breaking performance of the tested circuit breaker meets the requirements;

The mechanical performance test is used to detect and judge whether the mechanical reliability of the tested circuit breaker meets the requirements;

If any of the internal arcing withstand performance test, external insulation performance test, DC no-charge current breaking test, and mechanical performance test fails, the circuit breaker under test is judged to be unqualified;

If the internal arc resistance performance test, the external insulation performance test, the DC no-charge current breaking test, and the mechanical performance test are all passed, then the tested circuit breaker will be comprehensively evaluated for performance rating.

Compared with the prior art, the present invention has the following beneficial effects:

Through the four inspection tests of internal arc resistance performance testing, external insulation performance testing, DC no-charge current interruption testing, and mechanical performance testing, it is possible to conduct comprehensive and comprehensive performance testing and judgment on HSS to determine its performance. Whether it meets the performance requirements of use and guarantees the safety of use.

Description of the drawings

FIG. 1 is a flowchart of a method for comprehensive performance evaluation of a DC high-speed switch provided by an embodiment of the present invention;

Figure 2 is the circuit schematic diagram of the arc withstand test circuit inside the DC high-speed switch;

Figure 3 is a schematic diagram of the evaluation system of the contact ablation state of the interrupter of the circuit breaker;

Figure 4 is a schematic diagram of infrared monitoring of the interrupter;

Figure 5 is a schematic diagram of the temperature rise assessment process;

Figure 6 is the circuit diagram of the DC high-speed switch DC no-charge current breaking test circuit.

Detailed ways

The content of the present invention will be further described in detail below with reference to the drawings and specific embodiments.

Examples:

Referring to FIG. 1, the comprehensive performance evaluation method of the DC high-speed switch provided by this embodiment mainly includes:

Through the above four inspection tests of internal arc resistance performance test, external insulation performance test, DC no-charge current breaking test, and mechanical performance test, a comprehensive and comprehensive performance test and judgment can be made on HSS to determine Whether it meets the performance requirements of use and guarantees the safety of use.

Specifically, the above-mentioned internal arcing tolerance performance detection test mainly includes two major steps including the construction of the test circuit and the test operation.

Among them, as shown in Figure 2, the test circuit is mainly composed of three circuits: a short circuit circuit 100, a rectifier circuit 200, and an arc monitoring circuit 300.

The short circuit circuit 100 includes an auxiliary circuit breaker AB2, an alternator G, and a short circuit transformer T. The alternator G, the short circuit auxiliary circuit breaker AB2, and the primary coil of the short circuit transformer T are connected in series to form a circuit.

The rectifier circuit 200 includes a first ammeter A1, a rectifier valve group V, a dry reactor L, a rectifier auxiliary circuit breaker AB1, and a current limiting resistor R. The rectifier valve group V is connected to the secondary coil of the short-circuit transformer T , The first ammeter A1 is installed on the coil connected to the rectifier valve V and the secondary coil of the short-circuit transformer T; one end of the current limiting resistor R is connected to the input end of the rectifier valve group V, and the other end is connected to the rectifier auxiliary circuit breaker One end of the reactor AB1 is connected; one end of the reactor L is connected to the output end of the rectifier valve group V.

The arc monitoring circuit 300 includes a first voltmeter V1, a second voltmeter V2, a second ammeter A2, and a characteristic parameter comprehensive monitoring device 30; the other end of the rectifier auxiliary circuit breaker AB1 is used to communicate with the tested circuit breaker T0 Phase connection; the characteristic parameter comprehensive monitoring device 30 is used to monitor the tested circuit breaker T0 to obtain the parameters required for the test; one end of the second ammeter A2 is connected to the other end of the current limiting resistor R, and the other end Connected to the tested circuit breaker T0 and grounded respectively; one end of the first voltmeter V1 is connected to the line connecting the second ammeter A2 and the tested circuit breaker T0, and the other end is grounded; one end of the second voltmeter V2 Connect to the line connecting the rectifier auxiliary circuit breaker AB1 and the tested circuit breaker T0, and the other end is grounded.

Through the synergy of the short circuit circuit, rectifier circuit, and arc monitoring circuit, the internal arc tolerance test scene of the DC high-speed switch can be simulated equivalently, and the circuit breaker can be verified under the rated pressure of the circuit breaker SF ₆ through the equivalent simulation circuit The performance of the device to withstand the ablation of the DC current of the system load in the system operation state.

Among them, in the test circuit, the circuit breaker under test (ie, the circuit breaker under test T0) starts to open from the closing position, and a direct current arc I _dc flows between the arc contacts of the circuit breaker under test (the specific amplitude is based on the specific amplitude). The calculation value of the most severe fault conditions of the project shall prevail, generally in the range of 3000-5000A)

The duration is t _ac (the specific time is subject to the fixed value of the protection blocking time of the flexible straight valve of the specific project, generally in the range of 300-500ms);

A total of n arcing resistance tests were carried out, and the specific times were determined based on the electrical life requirements of the equipment.

In the initial state, the tested circuit breaker T0 is in the closed state, and the auxiliary circuit breakers AB1 and AB2 are in the open state.

Parameter deviation requirements: the deviation of the DC amplitude I _dc from the engineering requirements is ±10%, the duration cannot exceed 0.5s, and the deviation of I _dc ² t is 0-10%.

Specifically, the bridge type converter valve V composed of controllable converter arms of the rectifying valve group V can be set to 6 pulses or 12 pulses.

The characteristic parameter comprehensive monitoring device used to monitor the tested circuit breaker includes:

Monitoring of mechanical characteristics to obtain the time-contact speed and time-contact stroke curves when the tested circuit breaker T0 is opened;

Infrared monitoring to obtain the changes in the surface temperature of the arc extinguishing chamber caused by the arc resistance of the circuit breaker under test;

Gas composition monitoring, to obtain the process of SF6 gas composition generation and evolution during the arc resistance process of the tested circuit breaker.

Specifically, the test operation steps include the following sub-steps:

1) Configure test loop parameters

According to the required value of the test current and the rated voltage of the generator, adjust the ratio of the short-circuit transformer, and then adjust the dry-type reactor in the rectification test circuit to enable the circuit breaker under test to generate a short-circuit current with a DC amplitude I _dc .

2) Generate short-circuit current

Before the test circuit is short-circuited, the circuit breaker under test is in the closed position. After the test is started, the auxiliary circuit breaker AB2 is closed to short-circuit the circuit, and the short-circuit current is amplified with the coil turns ratio through the short-circuit transformer T to generate the short-circuit current required by the test, which is input into the rectifier valve of the rectifier circuit by an ammeter A1 records the current amplitude in real time.

3) Rectification

In the rectifier circuit, the bridge converter valve V composed of controllable converter arms can be set to 6 pulses or 12 pulses. After the AC short-circuit current is rectified by the converter valve, the auxiliary circuit breaker AB1 is closed and the DC current is output. After the dry-type reactor L and the current-limiting resistor R are adjusted, the current amplitude I _dc that meets the test requirements is generated.

4) Arcing test and condition monitoring

In the arc monitoring circuit, after the rated DC current flows through the tested circuit breaker T0, the tested circuit breaker T0 is controlled to open. With the rapid relative opening movement of the contacts, a DC arc is generated between the arc contacts and the contacts After the switch is opened in place, the DC arc will continue to ablate between the arc contacts. After the test requires time t _ac , the auxiliary circuit breaker AB2 will disconnect the AC short circuit circuit, cut off the power supply and measure the energy supply. The tested circuit breaker T0 arc contacts The arc gradually weakened and eventually extinguished. At this point, an experiment is over. Perform n tests according to the required value of the test. The test interval should be based on the time required for the temperature of the circuit breaker to be tested to return to the ambient temperature to avoid personal injury.

During the test, key parameters such as dynamic resistance, evolution of gas composition, opening and closing speed, and infrared temperature rise of the arc extinguishing chamber were recorded respectively, and based on these parameters, it was analyzed whether the DC arcing withstand capability of the tested circuit breaker meets the requirements Claim.

Specifically, the dynamic resistance includes 4 key characteristic parameters, which are specifically defined as follows:

1) Effective contact state of the arc contact: During the opening and closing process of the circuit breaker, when the contact resistance of the arc contact is less than or equal to a certain threshold (the value can be given by referring to the measured value of the dynamic contact resistance), it is considered arc contact The head belongs to the effective contact state. When the contact resistance is greater than this value, the arc contact is considered to be an invalid contact and is a separated state (not absolute separation, but to facilitate data analysis). Since the test current reaches more than 2000A during the dynamic resistance test, when the metal of the arc contact is absolutely separated, there will be a short arc phenomenon. It is inaccurate to use the test method to use the infinite contact resistance as the absolute contact separation time. Therefore, this application defines A certain threshold is used as the edge value of the arc contact, only for the convenience of the trend analysis of the test data.

2) Effective contact displacement L (mm): In the opening and closing process of the circuit breaker, just after the main contact is separated, the contact displacement corresponding to the arc contact contact resistance is less than or equal to the threshold (2000μΩ), called effective contact Displacement.

3) Cumulative contact resistance R _accu (μΩ*mm): the cumulative value of the contact resistance at the sampling time corresponding to the effective contact displacement. The sampling rate of the test instrument is 20k, that is, the corresponding contact resistance value is obtained every 0.05ms, and the contact resistance within the effective contact displacement curve range is integrated to obtain the cumulative contact resistance μΩ*mm.

4) Average contact resistance R _ave (μΩ/mm): The cumulative contact resistance is divided by the effective contact displacement to get the average contact resistance μΩ/mm, which can better reflect the changes in contact resistance and effective contact displacement after contact ablation .

Measure the dynamic resistance of the arc contact of the circuit breaker before and after the arc test and at each test interval, record the characteristic parameters of the arc contact ablation state, evaluate the arc ablation resistance of the arc contact, and complete the records in the following table.

When the effective contact displacement L of the arc contact is in the interval of 0～5mm, the average contact resistance shows a rapid downward trend with the increase of the effective contact displacement. After the contact displacement is greater than 5mm, the average contact resistance changes gradually to stabilize.

Before and after the arc resistance test, the size, length and weight change of the arc contact should be recorded.

Disassemble the test prototype to measure the port size and component weight of the dynamic and static arc contacts;

Weight change before and after the test (unit: g)

Change of arc contact size before and after the test (unit: mm)

Among them, the evaluation method of the contact ablation state of the interrupter of the circuit breaker is shown in Fig. 3, including the following steps:

The first step: the user extracts the characteristic parameters of the circuit breaker interrupter through the dynamic resistance test technology, and inputs them to the evaluation system. The input data includes:

1) Ledger information of the circuit breaker to be evaluated: circuit breaker dispatch number, phase, voltage level, circuit breaker model, manufacturer, commissioning time;

2) The initial characteristic parameters of this type of circuit breaker: the effective contact displacement of the arc contact L (mm); the cumulative contact resistance of the arc contact R _accu (μΩ*mm); the average contact resistance of the arc contact R _ave (μΩ/mm);

3) The characteristic parameters of the current state of the circuit breaker to be evaluated: the effective contact displacement of the arc contact L (mm); the cumulative contact resistance of the arc contact R _accu (μΩ*mm); the average contact resistance of the arc contact R _ave (μΩ/mm) ；

Step 2: Based on the database (accumulated energy ablation fingerprint library; contact characteristic parameter correlation library; contact ablation state expert library), synthesize the characteristic parameters of the initial state and current state of the circuit breaker to be evaluated input in the first step After evaluation, the cumulative opening and closing energy corresponding to the current ablation state of the arc contact and the quantitative difference of the characteristic quantity correlation curve are obtained.

The third step: Based on the results of the comprehensive analysis of the second step, the calculation of characteristic parameters is completed, and the ratio range of the effective contact displacement of the current arc contact of the circuit breaker to the initial effective contact displacement is judged.

Step 4: Evaluate the current state of the interrupter chamber of the circuit breaker. For example, if the ratio of the effective contact displacement of the current arc contact to the initial effective contact displacement is within the range of 80-100%, it belongs to the normal ablation state; if the ratio is 60-80 In the range of %, it belongs to a slightly ablated state; if the ratio is in the range of 40-60%, it belongs to a moderate ablation state; if the ratio is in the range of 20-40%, it belongs to a severe ablation state; if the ratio is in the range of <20% , Belong to an abnormal state;

During the internal arcing test of the circuit breaker, the evolution trend of the generation and growth of various characteristic components of the SF ₆ gas in the arc extinguishing chamber is recorded. This data can be used as an important maintenance basis for this type of circuit breaker during operation, as well as an evaluation An important indicator of the ablation degree of the circuit breaker nozzle.

For monitoring the opening and closing speed of the tested circuit breaker, a conventional speed sensor can be used to install on the arm of the operating mechanism of the circuit breaker. When the tested circuit breaker T0 opens and closes, the opening and closing speed is changed. The data of v-time t-action stroke l is transmitted in real time to the characteristic parameter comprehensive monitoring device for comprehensive processing.

When the tested circuit breaker T0 carries out the internal arc resistance test, since the arc contacts continue to withstand the ablation of the arc tarc, the temperature rise of the arc is radiated to the insulating jacket of the arc extinguishing chamber via the insulating gas, which will cause arc extinguishing The temperature rise of the chamber surface is a few K. Therefore, during the test, infrared monitoring devices are used based on infrared radiation temperature measurement technology to monitor the temperature rise of the insulation jacket of the interrupter of the circuit breaker in real time, and transmit the data to the comprehensive monitoring device for characteristic parameters Conduct comprehensive analysis and evaluation. In the type test, the temperature rise test data will be used as the basis for important state evaluation after operation.

The circuit breaker has two arc extinguishing chambers, and the temperature measurement points of each arc extinguishing chamber are respectively taken from the upper and lower layers. There are 6 points in the left, middle and right positions, as shown in Figure 4.

After completing the temperature measurement, record the temperature rise (K) data as follows:

The temperature rise assessment process is shown in Figure 5, including:

1. During the arc resistance test of the circuit breaker, the temperature of the insulation jacket of the arc extinguishing chamber is monitored by infrared, and the temperature rise test is carried out according to the principle of the upper and lower layers, the left, middle and right points. The temperature rise of each point is recorded as T2. The scatter temperature rise is processed by the root of variance to obtain the mean value T1.

2. Whether there is local overheating and arc extinguishing and the room temperature rise exceeds the average value T1max, if it does not exceed the evaluation normal, if it exceeds, proceed to the next evaluation.

3. According to the normal arc withstand temperature rise of the current-carrying conductor, the measured temperature rise of the jacket is inversely calculated to obtain the calculated value of the current-carrying conductor temperature rise.

4. Whether the test value of the scattered points of the arc extinguishing chamber exceeds the first limit value T2max1, if yes, it is evaluated as abnormal contact of the current-carrying conductor of the arc extinguishing chamber, if not, proceed to the next evaluation.

5. Whether the test value of the scattered point of the arc extinguishing chamber exceeds the first limit T2max2, if it is, it is assessed that the current-carrying conductor contact of the arc extinguishing chamber has reached the attention value, and other auxiliary evaluation methods should be adopted. If not, the temperature rise evaluation ends .

According to the required value of the test, after n times of internal arc resistance, during the test, the tested circuit breaker T0 should not produce obvious external effects, that is, the test product cannot explode, and there can be no holes or cracks on the shell. It meets the requirements of internal arc resistance performance.

The verification of mechanical reliability can be carried out in the following ways:

Due to the particularity of the position of the HSS switch in the DC system, extremely high mechanical reliability is required, and mechanical defects such as refusal to move, malfunction, jamming, etc. are not allowed during operation. The conventional mechanical performance M2 level 10000 is completed in accordance with the standard. After the second mechanical opening and closing operations, the mechanical limit condition test should also be added. The following is the proof of the mechanical reliability at the limit speed for the spring operating mechanism circuit breaker and the hydraulic (including hydraulic disc spring) mechanism. After completing the test conditions in the following table After the middle operation, the circuit breaker did not appear to fail to operate, malfunction, jam, etc., and the hydraulic mechanism did not leak oil, frequent pressure, and failed to build pressure. The test passed.

1. Spring operating mechanism circuit breaker

The opening and closing speed range of the supplied equipment is to verify the mechanical operation performance of the equipment at the fastest opening and closing speed and the slowest opening and closing speed (each carried out no less than 500 times). During the test, there should be no abnormal actions. After the test, the test product should be checked for abnormal damage.

Test conditions

2. Hydraulic (including hydraulic disc spring) mechanism circuit breaker

In the mechanical operation at the limit opening and closing speed, under the rated oil pressure, adjust the throttle valve of the hydraulic mechanism to make the opening and closing speeds reach their upper and lower limits respectively, and carry out the limit speed mechanical operation after the combination to verify the mechanical action reliability. Before and after the test, record and compare the range of opening and closing speed changes.

Test conditions

The DC no-charge current interruption detection test mainly includes two major steps, one is to construct a test circuit, and the other is to perform a test operation on the test circuit.

Among them, as shown in Figure 6, the test circuit includes a circuit including the first auxiliary circuit breaker AB1, the second auxiliary circuit breaker AB2, the capacitor bank C, the resistor R, the ammeter A, the first voltmeter V 1, and the second voltmeter. V2 and DC high voltage generator DC.

Wherein, the DC high voltage generator CC, the second auxiliary circuit breaker AB2 and the capacitor bank C are connected in series to form a loop; the capacitor bank C, the resistor R and the second voltmeter V2 are connected in series to form a loop; the first auxiliary circuit breaker One end of the device AB1 is connected to the resistor R, and the other end is used to connect to one end of the tested circuit breaker T0; one end of the first voltmeter V1 is connected to the first auxiliary circuit breaker AB1 and the tested circuit breaker T0 The other end is connected to the phase connection line of the second voltmeter V2 and capacitor bank C; one end of the ammeter A is used to connect to the other end of the tested circuit breaker T0, and the other end is grounded and connected to On the line connecting the second voltmeter V2 and the capacitor bank C.

In the initial state, the first auxiliary circuit breaker AB1 and the second auxiliary circuit breaker AB2 are in the open state, the tested circuit breaker T0 is in the closed state, and the DC high voltage generator DC can output the DC high voltage to the capacitor bank C to a specified value.

Specifically, when the DC no-charge current breaking test circuit of the DC high-speed switch is tested, it includes the following steps:

1) Configure test loop parameters

According to the breaking DC current I and the recovery voltage U of the test target, the resistor R=U/I is obtained;

The configuration of the capacitor bank mainly determines the capacitance C of the capacitor bank and the internal resistance R _C of the capacitor bank. After the capacitor bank is charged, the pre-charged capacitor bank and the resistive load form a DC current loop, so the capacitor parameters can be based on the following The formula is obtained.

I=(U+IR _C )ωC

The cooperative operation interval T1 between the auxiliary circuit breaker AB2 and the auxiliary circuit breaker AB1, and the cooperative operation interval T2 between the auxiliary circuit breaker AB1 and the tested circuit breaker T0, must not exceed the time t for the current to decay to I after the test circuit is turned on, otherwise The breaking current of the tested circuit breaker will be less than the required value I, which is determined by the overall time constant of the specific circuit, which can be obtained by the following formula.

Ln is the logarithm of the natural constant.

The voltage level and range of ammeter A, voltmeter V1, V2 should be higher than the test requirements.

2) Capacitor bank energy storage

The auxiliary circuit breaker AB2 is closed, and the DC high-voltage generator DC charges and stores the capacitor bank. After reaching U+IR _C or above, the auxiliary circuit breaker AB2 opens.

3) Discharge the capacitor bank

After the delay of the T1 operation interval, the auxiliary circuit breaker AB1 is closed, the test circuit is turned on, and affected by the RC circuit, the circuit current has a certain attenuation range. Before the test current I is attenuated, the tested circuit breaker T0 passes the T2 operation interval The gate will be opened after a time delay.

4) Break DC current

During the opening process of the circuit breaker T0, a DC arc will be generated at the break of the switch. The DC arc can be equivalent to a dynamic resistance; as the opening process proceeds, the distance between the moving and static arc contacts gradually increases, and the DC current The arc resistance gradually increases, the voltage at both ends of the switch also gradually increases, and the loop current gradually decreases; when the current is small to a certain level, the arc burning is difficult to maintain and the arc is extinguished. At this time, record the T3 arcing time. It is required that the product of the T3 arcing time and the average opening speed v of the circuit breaker must be less than the design distance L of the contact, otherwise the opening movement will stop and the DC arc cannot be extinguished, which will cause the opening failure.

5) Test criteria

The initial state of the tested circuit breaker is the closing position, the circuit is connected by the auxiliary switch of the circuit, and then the circuit breaker under test is opened at the on-current time T2. After the arcing time T3, the tested circuit breaker will normally open the test current I. , After breaking, the arc contact can withstand the recovery voltage U without heavy breakdown.

The positive and negative polarity were tested 10 times each.

The tested circuit breaker (namely, the tested circuit breaker) has completed the specified positive and negative polarity DC no-charge current breaking times m, and it can be judged as the test passed.

The external insulation performance test can be determined by the design of the external insulation dry arc distance and creepage distance of the circuit breaker, as well as the insulation characteristics of the external insulation under climatic conditions such as humidity, pollution or salt spray.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and their purpose is to enable those of ordinary skill in the art to understand the content of the present invention and implement them accordingly, and should not limit the protection scope of the present invention. All equivalent changes or modifications made according to the essence of the present invention should be covered by the protection scope of the present invention.

Claims

A method for evaluating the comprehensive performance of a DC high-speed switch, which is characterized in that it includes:

Internal arcing tolerance performance testing test, used to detect and judge whether the burning tolerance performance of the tested circuit breaker meets the requirements;

External insulation performance inspection test to detect whether the insulation margin of the tested circuit breaker meets the requirements;

DC no-charge current breaking detection test, used to detect and judge whether the breaking performance of the tested circuit breaker meets the requirements;

The mechanical performance test is used to detect and judge whether the mechanical reliability of the tested circuit breaker meets the requirements;

If any of the internal arcing withstand performance test, external insulation performance test, DC no-charge current breaking test, and mechanical performance test fails, the circuit breaker under test is judged to be unqualified;

If the internal arc resistance performance test, the external insulation performance test, the DC no-charge current breaking test, and the mechanical performance test are all passed, then the tested circuit breaker will be comprehensively evaluated for performance rating.
The method according to claim 1, wherein the internal arcing tolerance performance testing test comprises:

Steps to construct test circuit:

The test circuit includes a short circuit circuit, a rectifier circuit and an arc monitoring circuit; among them:

The short-circuit circuit includes a short-circuit auxiliary circuit breaker, an AC power supply, and a short-circuit transformer; the AC power supply, the short-circuit auxiliary circuit breaker, and the primary coil of the short-circuit transformer are connected in series to form a circuit;

The rectifier circuit includes a first ammeter, a rectifier valve group, a reactor, a rectifier auxiliary circuit breaker, and a current limiting resistor; the rectifier valve group is connected to the secondary coil of the short-circuit transformer, and the first ammeter is installed on the rectifier valve and On the coil connected to the secondary coil of the short-circuit transformer; one end of the current limiting resistor is connected to the input end of the rectifier valve group, and the other end is connected to one end of the rectifier auxiliary circuit breaker; one end of the reactor is connected to The output ends of the rectifier valve group are connected;

The arc monitoring circuit includes a first voltmeter, a second voltmeter, a second ammeter, and a characteristic parameter comprehensive monitoring device; the other end of the rectifier auxiliary circuit breaker is used to connect with the circuit breaker under test; the characteristic parameter The integrated monitoring device is used to monitor the circuit breaker under test to obtain the parameters required for the test; one end of the second ammeter is connected to the other end of the current limiting resistor, and the other end is connected to the circuit breaker under test. Grounding; one end of the first voltmeter is connected to the line connecting the second ammeter and the circuit breaker under test, and the other end is grounded; one end of the second voltmeter is connected to the phase of the rectifier auxiliary circuit breaker and the circuit breaker under test On the connected line, the other end is grounded;

Test operation steps, including:

The sub-steps of configuring test loop parameters include:

According to the required value of the test current and the rated voltage of the generator, adjust the ratio of the short-circuit transformer, and then adjust the dry-type reactor in the rectification test circuit so that the circuit breaker under test can generate a short-circuit current of the DC amplitude I dc ;

The sub-step of generating short-circuit current includes:

Before the test circuit is short-circuited, the tested circuit breaker is in the closed position; after the test starts, the short-circuit auxiliary circuit breaker is closed to short-circuit the circuit, and through the short-circuit transformer, the short-circuit current is amplified with the coil turns ratio to generate test requirements The short-circuit current is input into the rectifier valve of the rectifier circuit, and the current amplitude is recorded by the first ammeter in real time;

The commutator sub-step includes:

After the AC short-circuit current is rectified by the converter valve, the rectifier auxiliary circuit breaker is closed and the DC current is output. After being adjusted by the dry reactor and current-limiting resistor, the current amplitude I dc meeting the test requirements is generated;

The arc test and condition monitoring sub-steps include:

In the arc monitoring circuit, after the rated DC current flows through the circuit breaker under test, the circuit breaker under test is controlled to open. With the rapid relative opening of the contacts, a DC arc is generated between the arc contacts, and the contacts are opened. After being in place, the DC arc will continue to ablate between the arc contacts. After the test requires time t ac , the short-circuit auxiliary circuit breaker will disconnect the AC short-circuit circuit and cut off the power supply to measure the energy supply. The tested circuit breaker T0 arc contact arc Gradually weaken and finally extinguished; at this point, one test is over, and n tests are performed according to the test requirements. The test interval should be based on the time required for the temperature of the circuit breaker to be tested to return to the ambient temperature; during the test, record the test separately The dynamic resistance of the circuit breaker, the evolution of the gas composition, the opening and closing speed, and the infrared temperature rise parameters of the interrupter; where n is a positive integer.
The method according to claim 2, wherein the arc monitoring circuit further comprises a characteristic parameter comprehensive monitoring device, and the characteristic parameter comprehensive monitoring device is used to monitor the circuit breaker under test to obtain the parameters required for the test .
The method according to claim 3, wherein the characteristic parameter comprehensive monitoring device for monitoring the circuit breaker under test comprises:

Monitoring of mechanical characteristics to obtain the time-contact speed and time-contact stroke curves when the tested circuit breaker T0 is opened;

Infrared monitoring to obtain the changes in the surface temperature of the arc extinguishing chamber caused by the arc resistance of the circuit breaker under test;

Gas composition monitoring, to obtain the process of SF6 gas composition generation and evolution during the arc resistance process of the tested circuit breaker.
The method according to claim 1, wherein the DC no-charge current interruption detection test comprises:

Steps to construct test circuit:

The test circuit includes a first auxiliary circuit breaker, a second auxiliary circuit breaker, a capacitor bank, a resistor, an ammeter, a first voltmeter, a second voltmeter, and a DC high-voltage generator; wherein,

The DC high voltage generator, the second auxiliary circuit breaker and the capacitor bank are connected in series to form a loop;

The capacitor bank, the resistor and the second voltmeter are connected in series to form a loop;

One end of the first auxiliary circuit breaker is connected to the resistor, and the other end is used to connect to one end of the circuit breaker under test;

One end of the first voltmeter is connected to the line between the first auxiliary circuit breaker and the circuit breaker under test, and the other end is connected to the phase connection line of the second voltmeter and the capacitor bank;

One end of the ammeter is used to connect with the other end of the circuit breaker under test, and the other end is grounded and connected to the line connecting the second voltmeter and the capacitor bank;

Test operation steps, including:

The sub-steps of configuring test loop parameters include:

According to the breaking DC current I and the recovery voltage U of the test target, the resistor R=U/I is obtained;

Configure the capacitor bank, mainly determine the capacitance C of the capacitor bank and the internal resistance R C of the capacitor bank;

The cooperative operation interval T1 between the second auxiliary circuit breaker and the first auxiliary circuit breaker, and the cooperative operation interval T2 between the second auxiliary circuit breaker and the tested circuit breaker, must not exceed the time t for the current to decay to I after the test circuit is turned on. , Otherwise the breaking current of the tested circuit breaker will be less than the required value I;

The voltage level and range of the ammeter, the first voltmeter and the second voltmeter should be higher than the test requirements;

The sub-step of capacitor bank energy storage includes:

The second auxiliary circuit breaker is closed, and the DC high-voltage generator charges and stores energy to the capacitor bank. After reaching U+IR C or higher, the second auxiliary circuit breaker opens;

The steps of discharging the capacitor bank include:

After the delay of the T1 operation interval, the first auxiliary circuit breaker is closed, the test circuit is turned on, and the circuit current decays. Before it decays to the test current I, the tested circuit breaker is opened after the delay of the T2 operation interval;

The sub-step of breaking the direct current includes:

During the opening process of the tested circuit breaker, a DC arc will be generated at its switch fracture, which is equivalent to a dynamic resistance; as the opening process proceeds, the distance between the dynamic and static arc contacts gradually increases. The DC arc resistance gradually increases, the voltage across the switch gradually increases, and the loop current gradually decreases; when the current is small to a certain level, the arc burning is difficult to maintain and the arc is extinguished. At this time, record the T3 arcing time; require T3 arcing The product of the time and the average opening speed v of the tested circuit breaker must be less than the designed distance L of the contact of the tested circuit breaker, otherwise the opening movement will stop and the DC arc cannot be extinguished, which will result in failure of the opening;

The test criterion sub-step includes:

The initial state of the tested circuit breaker is the closing position, the circuit is connected by the auxiliary switch of the circuit, and then the circuit breaker under test is opened at the on-current time T2. After the arcing time T3, the tested circuit breaker will normally open the test current I. , After breaking, the arc contact can withstand the recovery voltage U without heavy breakdown;

The tested circuit breaker has completed the specified positive and negative polarity DC no-charge current breaking times m, it is judged as the test passed; m is a positive integer.
The method according to claim 5, wherein the time t is calculated by the following formula:

Ln is the logarithm of the natural constant.