CN107942242A - High-voltage AC breaker Characteristics Detection evaluation method based on arc extinguishing electromagnetic waveforms - Google Patents

Abstract

The invention discloses a characteristic detection and evaluation method of a high-voltage AC circuit breaker based on an arc-extinguishing electromagnetic waveform, which solves the technical problem of real-time detection of the arc-extinguishing characteristic of the AC circuit breaker. For a running high-voltage AC circuit breaker, during the opening and closing process, the current between the moving and static contacts increases rapidly, and a sudden magnetic field will be generated in the space, which then excites a sudden electric field, which in turn excites a The abruptly changing magnetic field excites an electromagnetic wave signal in space; the present invention uses a radio frequency sensor to detect the electromagnetic wave signal, and when the arc extinguishing performance of the circuit breaker decreases, its arc extinguishing speed also decreases, and during the breaking process of the AC circuit breaker, there will be By stimulating multiple electromagnetic wave signals, the arc extinguishing performance of the AC circuit breaker can be evaluated by the number and duration of the electromagnetic wave signals tested during the breaking process. The measurement accuracy of the device is very high, reaching nanosecond level, which is much higher than the 0.01 millisecond accuracy of the existing stroke method.

Description

Detection and evaluation method of high-voltage AC circuit breaker characteristics based on arc-extinguishing electromagnetic waveform

technical field

The invention belongs to the field of high-voltage electrical switches, and in particular relates to a method for detecting and evaluating arc extinguishing characteristics of an ultra-high voltage or ultra-high voltage circuit breaker.

Background technique

High-voltage AC circuit breaker is one of the important equipment in the power system. It plays a role in control and protection in the operation of the power grid. Its operating performance directly affects the stability of power system operation and the reliability of power supply. How to effectively detect and regularly evaluate the working status of high-voltage AC circuit breakers, discover early defects of circuit breakers in time, and prevent the occurrence of vicious accidents such as switch explosions have important practical significance. The arc extinguishing characteristic is the most important performance of a high voltage circuit breaker. The decline of the arc extinguishing ability of an AC circuit breaker will lead to major accidents. The number of AC circuit breakers in the power grid is huge, and the existing technology cannot effectively detect and evaluate its arc extinguishing characteristics. . At present, the detection methods of high-voltage AC circuit breakers include stroke method and electrical life method. The stroke method is mainly to measure the stroke characteristics of the high-voltage circuit breaker, which can directly reflect the opening and closing time and speed characteristics of the circuit breaker, but this method cannot realize online detection; the device needs to be powered off during detection, the test interval is long, and the data lacks continuity. Changes in switch performance cannot be reflected in time; in addition, the detection is done at both ends of each port of the circuit breaker, and also in the operation control circuit of the switch. Operation, for the substation in operation, the security risk of this operation method is too great. The electrical life method is to install a current sensor on the circuit breaker to detect the effective value of the breaking current, and calculate the electrical life of the circuit breaker after weighted accumulation with the number of breaking times, so as to indirectly detect and evaluate its arc extinguishing characteristics; The method can only reflect the overall change trend of the arc extinguishing characteristics of the circuit breaker, but cannot reflect the sudden arc extinguishing characteristics of the circuit breaker in real time.

Contents of the invention

The invention provides a method for detecting and evaluating the characteristics of a high-voltage AC circuit breaker based on an arc-extinguishing electromagnetic waveform, which solves the technical problem of real-time detection of the arc-extinguishing characteristics of the AC circuit breaker.

The present invention solves the above technical problems through the following technical solutions:

The general idea of the present invention is: during the breaking and closing process of the high-voltage AC circuit breaker in operation, the current between the moving and static contacts increases rapidly, and a sudden change magnetic field will be generated in the space, which then excites a sudden change electric field , the electric field then excites a sudden change in the magnetic field, which excites an electromagnetic wave signal in space; the present invention uses a radio frequency sensor to detect the electromagnetic wave signal, and when the arc extinguishing performance of the circuit breaker decreases, its arc extinguishing speed also decreases, and the arc extinguishing speed also decreases during AC open circuit During the breaking process of the circuit breaker, multiple electromagnetic wave signals will be excited, and the arc extinguishing performance of the AC circuit breaker can be evaluated by the number and duration of the electromagnetic wave signals tested during the breaking process.

A high-voltage AC circuit breaker arc extinguishing characteristic detection device, including a high-voltage AC circuit breaker arc extinguishing chamber, a static contact and a moving contact are arranged in the high-voltage AC circuit breaker arc extinguishing chamber, and the moving contact passes through a contact spring and an insulating pull rod Connected together, the other end of the insulating pull rod is connected with the operating mechanism, and a radio frequency sensor is arranged on one side of the arc extinguishing chamber of the high voltage AC circuit breaker, and the radio frequency sensor is connected with a high-speed oscilloscope through a signal amplifier. When the moving contact and the static contact contact and separate, an arc is generated in the arc extinguishing chamber, and the arc is excited to generate an electromagnetic wave signal. The electromagnetic wave signal is collected by a radio frequency sensor, amplified by a signal amplifier, and the electromagnetic wave is obtained by a high-speed oscilloscope. Signal.

A method for detecting and evaluating the characteristics of a high-voltage AC circuit breaker based on an arc-extinguishing electromagnetic waveform, characterized by the following steps:

The first step is to install a radio frequency sensor on one side of the arc extinguishing chamber of the high voltage AC circuit breaker, and connect the radio frequency sensor to a high-speed oscilloscope through a signal amplifier;

The second step is to detect the surrounding space environment of the high-voltage AC circuit breaker interrupter through the radio frequency sensor, and record the external interference signals of the surrounding space environment;

The third step, when the high-voltage circuit breaker is opening and closing, collect the radiated electromagnetic wave signal at the fracture of the high-voltage AC circuit breaker through the radio frequency sensor;

The fourth step is to judge the fault type of the high-voltage circuit breaker according to the collected radiation electromagnetic wave signal at the fracture of the high-voltage AC circuit breaker. The specific steps are as follows:

A. If there are multiple peaks in the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker, the dynamic and static contacts have closed and bounced;

B. If the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker lasts for more than 1-1.5 seconds, the operating mechanism is stuck;

C. If the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker is a continuous arc waveform, that is, the radiated electromagnetic wave signal always exists, then the closing of the dynamic and static contacts is not in place;

D. If the starting time of the collected three-phase radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker is different, there will be inconsistencies in the synchronism of the three-phase dynamic and static contact closing.

Compared with the traditional measurement and evaluation method of high-voltage circuit breaker motion characteristics, firstly, the sensor of the present invention has no mechanical or electrical connection with the circuit breaker body, and the measurement does not require any changes to the circuit breaker body, no power failure, no wiring, and can be carried out conveniently On-line measurement; secondly, the measurement accuracy of this device is very high, up to nanosecond level, which is much higher than the 0.01 millisecond accuracy of the existing travel method; finally, the arc extinguishing characteristics during the opening and closing process of the circuit breaker can be evaluated at the same time .

Description of drawings

Fig. 1 is a schematic diagram of the acquisition structure of radiated electromagnetic wave signals of the present invention;

Figure 2 is a schematic diagram of the structure of the radiated electromagnetic wave signal acquisition of the phase-splitting high-voltage circuit breaker;

Figure 3 is the radiated electromagnetic wave signal during the opening and closing process of the high-voltage circuit breaker under normal conditions;

Figure 4 is the radiated electromagnetic wave signal during the closing process of the high-voltage circuit breaker when the moving and static contacts have a closing bounce fault;

Figure 5 shows the radiated electromagnetic wave signal during the closing process of the high-voltage circuit breaker when the operating mechanism is stuck;

Figure 6 shows the radiated electromagnetic wave signal during the closing process of the high-voltage circuit breaker when the moving and static contacts fail to close in place;

Figure 7 shows the radiated electromagnetic wave signal during the closing process of the high-voltage circuit breaker when the closing synchronism of the three-phase dynamic and static contacts is inconsistent.

Detailed ways

The present invention is described in detail below in conjunction with accompanying drawing:

A method for detecting and evaluating the characteristics of a high-voltage AC circuit breaker based on an arc-extinguishing electromagnetic waveform comprises the following steps:

The first step is to install a radio frequency sensor 1 on one side of the arc extinguishing chamber 5 of the high-voltage AC circuit breaker, and the radio frequency sensor 1 is connected with the high-speed oscilloscope 3 through the signal amplifier 2;

The second step is to detect the surrounding space environment of the arc extinguishing chamber 5 of the high-voltage AC circuit breaker through the radio frequency sensor 1, and record the external interference signals of the surrounding space environment;

In the third step, when the high-voltage circuit breaker performs opening and closing operations, the radiated electromagnetic wave signal at the fracture of the high-voltage AC circuit breaker is collected through the radio frequency sensor 1;

The fourth step is to judge the fault type of the high-voltage circuit breaker according to the collected radiation electromagnetic wave signal at the fracture of the high-voltage AC circuit breaker. The specific steps are as follows:

A. If there are multiple peaks in the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker, the dynamic and static contacts have closed and bounced;

B. If the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker lasts for more than 1-1.5 seconds, the operating mechanism is stuck;

C. If the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker is a continuous arc waveform, that is, the radiated electromagnetic wave signal always exists, then the closing of the dynamic and static contacts is not in place;

D. If the starting time of the collected three-phase radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker is different, there will be inconsistencies in the synchronism of the three-phase dynamic and static contact closing.

Firstly, connect the three RF sensors to the signal amplifier, and connect the signal amplifier to the high-speed oscilloscope; point the RF sensor at the space around the device under test, detect the background environment of the device under test, and eliminate the influence of external interference signals; then, place the The three radio frequency sensors are aimed at the three-phase fractures of A, B, and C. When the high-voltage circuit breaker is in the opening and closing operation, the electromagnetic wave signal radiated by the high-voltage circuit breaker can be measured through the high-speed oscilloscope; analyze and judge the high-voltage circuit breaker in the process of opening and closing. If there is no abnormal signal for the electromagnetic wave signal generated in the circuit breaker, it is judged that the circuit breaker is in good operating condition.

(1) When the dynamic and static contacts have a closing bounce failure: when the moving and static contacts close and bounce, multiple re-ignitions occur between the moving and static contacts, that is, when the moving and static contacts are closed, the arc is extinguished, and the moving and static contacts bounce off the arc Therefore, the radiated electromagnetic wave signal will have multiple peaks, and the waveform is shown in Figure 4;

(2) When the operating mechanism jams: When the operating mechanism jams, the movement process of the mechanism is not smooth enough. Compared with normal conditions, the duration of the radiated electromagnetic wave signal is longer. The waveform is shown in Figure 5. ;

(3) Fault when the closing of the dynamic and static contacts is not in place: When the failure of the closing of the moving and static contacts is not in place, and the moving and static contacts fail to close, a continuous arc is generated, that is, the radiated electromagnetic wave signal always exists, and the waveform is shown in As shown in Figure 6;

(4) When the closing synchronism of the three-phase dynamic and static contacts is inconsistent: when the three-phase dynamic and static contacts are not in the same period, that is, the closing time of the three-phase dynamic and static contacts of A, B, and C is inconsistent, then the dynamic and static contacts will be generated. The time of the arc is also inconsistent, so the start time of the radiated electromagnetic wave signal is different, and the waveform is shown in Figure 7;

After the detection is completed, the detected electromagnetic wave signal is saved by a high-speed oscilloscope for the next step of data analysis.

Claims (1)

1. A method for detecting and evaluating the characteristics of a high-voltage AC circuit breaker based on an arc-extinguishing electromagnetic waveform, characterized in that the following steps: The first step is to install a radio frequency sensor (1) on one side of the arc extinguishing chamber (5) of the high-voltage AC circuit breaker, and the radio frequency sensor (1) is connected with the high-speed oscilloscope (3) through the signal amplifier (2); The second step is to detect the surrounding space environment of the high-voltage AC circuit breaker interrupter (5) through the radio frequency sensor (1), and record the external interference signals of the surrounding space environment; The third step, when the high-voltage circuit breaker is opening and closing, collect the radiated electromagnetic wave signal at the fracture of the high-voltage AC circuit breaker through the radio frequency sensor (1); The fourth step is to judge the fault type of the high-voltage circuit breaker according to the collected radiation electromagnetic wave signal at the fracture of the high-voltage AC circuit breaker. The specific steps are as follows: A. If there are multiple peaks in the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker, the dynamic and static contacts have closed and bounced; B. If the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker lasts for more than 1-1.5 seconds, the operating mechanism is stuck; C. If the collected radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker is a continuous arc waveform, that is, the radiated electromagnetic wave signal always exists, then the closing of the dynamic and static contacts is not in place; D. If the starting time of the collected three-phase radiated electromagnetic wave signal waveform at the fracture of the high-voltage AC circuit breaker is different, there will be inconsistencies in the synchronism of the three-phase dynamic and static contact closing.