Vacuum circuit breaker time characteristic detection system and method based on transient electric signals

Abstract

The invention provides a transient electric signal-based vacuum circuit breaker time characteristic detection system and method, relates to the field of power system automation equipment, and broadens the research of the field of circuit breaker machinery and time characteristic detection systems. Comprising an opening and closing coil used for controlling the opening and closing operation of the circuit breaker; the voltage transformer is used for measuring the voltage at the two ends of the circuit breaker; the current sensor is used for measuring current flowing through the circuit breaker; the data acquisition instrument is used for receiving signals respectively output by the opening and closing coil, the angular displacement sensor, the voltage transformer and the current sensor and transmitting the signals to the upper computer; the upper computer is internally provided with a feature extraction algorithm and used for analyzing the relation between transient electric signals generated by the circuit breaker and time characteristic information, calibrating the just-open and just-close points of the circuit breaker in each online detection process of the circuit breaker, obtaining the time characteristic information of the current circuit breaker and achieving online detection of the time characteristics of the circuit breaker. The measurement result provided by the invention has higher timeliness and continuity.

Description

Technical Field

[0001] The present invention relates to the technical field of power system automation equipment, and is applied to the time characteristic detection process of a vacuum circuit breaker, and specifically relates to a vacuum circuit breaker time characteristic detection system and method based on transient electrical signals. Background Art

[0002] In the power system, vacuum circuit breakers, as key switching devices, play an important role in ensuring the safety and stable operation of the power grid. In order to ensure its reliable performance, regular time characteristic detection is essential. Traditionally, the time characteristic detection of vacuum circuit breakers mainly relies on mechanical characteristic testers. This method usually requires the circuit breaker to be tested to be disconnected from the power system and placed offline in order to access an instrument specially designed to measure the mechanical characteristics of the circuit breaker. The instrument can accurately measure important indicators such as the just-opening point and just-closing point of the circuit breaker under no-load conditions. These data will then be used to compare and analyze with pre-set standard values ​​or reference values ​​to evaluate the current working status of the circuit breaker and its potential problems.

[0003] However, this traditional approach has significant limitations. First, since the entire process must be performed with the circuit breaker completely out of the actual working environment, the results obtained may not fully reflect the actual situation of the circuit breaker when it is online. In particular, the behavior of the circuit breaker may vary under different load conditions, and these differences are difficult to reflect through offline testing. In addition, each implementation of such testing requires the arrangement of professional technicians to be on-site for operation, and is often accompanied by a long service interruption time, which poses a challenge to maintaining power supply continuity and reducing user inconvenience.

[0004] Furthermore, frequently shutting down circuit breakers to complete inspections will not only increase operating costs, but also bring additional human resource burdens to related companies. Considering the growing demand for high availability and low maintenance costs in modern power grids, existing solutions are obviously difficult to meet the new requirements of industry development. At the same time, the data obtained based on a single static measurement lacks a long-term tracking observation basis, making it difficult to achieve trend analysis of equipment health status and early fault warning, which undoubtedly limits the effectiveness of maintenance strategies.

[0005] In view of the existence of the above problems, it is particularly important to develop a new technology that can quickly and accurately monitor the time characteristics of vacuum circuit breakers without affecting normal power supply. Summary of the invention

[0006] Based on the current status of the background technology, the purpose of the present invention is to solve the problem that the current vacuum circuit breaker time characteristics are generally measured offline using mechanical characteristic testers, and therefore a vacuum circuit breaker time characteristic detection system and method based on transient electrical signals is proposed. Under the condition of normal operation of the power system, the present invention collects transient electrical signals generated when the circuit breaker is opened and closed, extracts features, and obtains time characteristic information such as the circuit breaker opening and closing points, thereby realizing online detection of the circuit breaker time characteristics and effectively ensuring the safe and stable operation of the power system.

[0007] The present invention adopts the following technical solutions to achieve the purpose:

[0008] In a first aspect, the present invention provides a vacuum circuit breaker time characteristic detection system based on transient electrical signals, the system comprising the following components:

[0009] An opening and closing coil is used to control the opening and closing operation of the circuit breaker to be tested;

[0010] A voltage transformer, connected to the power supply side of the circuit breaker, is used to measure the voltage across the circuit breaker;

[0011] A current sensor is wrapped around the branch bus of the circuit breaker and is used to measure the current flowing through the circuit breaker;

[0012] A data acquisition instrument is used to receive the signals output by the opening and closing coils, the angular displacement sensor, the voltage transformer and the current sensor, and transmit the received signals to the host computer;

[0013] The host computer has a built-in feature extraction algorithm, which is used to analyze the relationship between the transient electrical signal and the time characteristic information generated by the circuit breaker during the opening and closing operations through the feature extraction algorithm, calibrate the circuit breaker's opening and closing points during each online detection of the circuit breaker, and obtain the time characteristic information of the current circuit breaker based on the calibration results, thereby realizing online detection of the circuit breaker's time characteristics.

[0014] Specifically, the opening and closing coil controls the opening and closing operations of the circuit breaker to be detected by outputting an opening and closing voltage signal.

[0015] Specifically, when the circuit breaker performs opening and closing operations, the voltage measured by the voltage transformer includes a transient voltage signal, and the current sensor uses a Rogowski coil, and the current measured by it includes a transient current signal; the data acquisition instrument collects and receives transient voltage signals, transient current signals, and opening and closing voltage signals through multiple preset channels under preset sampling rate conditions.

[0016] Specifically, the host computer is also used to collect the transient electrical signals generated during the opening and closing operations of the circuit breaker under different circuit breaker operating conditions, and conduct comparative analysis based on the time characteristic information obtained from offline testing to obtain the relationship between the transient electrical signals and the corresponding time characteristic information, and determine the feature extraction algorithm.

[0017] Specifically, the time characteristic information includes the opening and closing points, the opening and closing time, the opening and closing speed, and the opening and closing travel.

[0018] In a second aspect, the present invention provides a method for detecting time characteristics of a vacuum circuit breaker based on a transient electrical signal, the method comprising the following steps:

[0019] S1. Use an angular displacement sensor to collect the travel-time curve and time characteristic information of the circuit breaker and transmit them to a mechanical characteristic tester to form offline comparison data based on the time characteristic information;

[0020] S2. When the circuit breaker is online, the voltage across the circuit breaker is measured by a voltage transformer, and the current flowing through the circuit breaker is measured by a current sensor;

[0021] S3, the data acquisition instrument collects the output signals of the opening and closing coils, the voltage transformer and the current sensor and transmits them to the host computer;

[0022] S4, changing the operating conditions of the circuit breaker, respectively collecting corresponding signals of the circuit breaker under different operating conditions, and combining the travel-time curve obtained in step S1 to determine the corresponding relationship between the transient electrical signal generated by the opening and closing operation and the time characteristic information of the circuit breaker;

[0023] S5. When the circuit breaker is online, the transient electrical signal generated by the circuit breaker during the opening and closing operation is extracted through a feature extraction algorithm. According to the corresponding relationship determined in step S4, the opening and closing points of the circuit breaker are calibrated, and the time characteristic information of the current circuit breaker is obtained by the host computer.

[0024] Furthermore, in step S5, when the circuit breaker performs a closing operation, the feature extraction algorithm determines the time point when the transient electrical signal last appears as the circuit breaker's just-closing point; when the circuit breaker performs an opening operation, the feature extraction algorithm determines the time point when the transient electrical signal first appears as the circuit breaker's just-opening point.

[0025] Preferably, when the time characteristic detection of the circuit breaker is performed by means of transient electrical signals, the transient voltage signal in the voltage measured by the voltage transformer is used as the main criterion, and the transient current signal in the current measured by the current sensor is used as the auxiliary criterion.

[0026] Specifically, when the host computer calculates the closing time of the current circuit breaker, the feature extraction algorithm obtains the triggering time point of the closing signal and the time point when the transient electrical signal last appears, and the difference between the two time points is obtained to obtain the closing time; when the host computer calculates the opening time of the current circuit breaker, the feature extraction algorithm obtains the triggering time point of the opening signal and the time point when the transient electrical signal first appears, and the difference between the two time points is obtained to obtain the opening time; the calculation formula is as follows:

[0027]

[0028] In the formula, t h is the time point when the transient electrical signal last appears during closing, t f It is the earliest time point when the transient electrical signal appears during opening. t1 and t2 are the triggering time points of the closing signal and the opening signal respectively.

[0029] In summary, due to the adoption of this technical solution, the beneficial effects of the present invention are as follows:

[0030] The present invention can realize real-time monitoring of the time characteristics of the circuit breaker and obtain a series of key time characteristic data without interfering with the normal operation of the power system. Compared with the traditional offline measurement method that relies on a mechanical characteristic tester, the measurement results provided by the present invention have higher timeliness and continuity. In addition, the relative error of the opening and closing time measurement value obtained by the present invention is strictly controlled within ±1%, ensuring high-precision data quality.

[0031] The present invention thus opens up a new research path in the field of online monitoring of mechanical and time characteristics of circuit breakers. Its technical approach can enrich the existing online monitoring system and provide a research direction for further exploration and development of circuit breaker performance evaluation in the future. After combining the present invention with remote monitoring functions and automated maintenance strategies, it is possible to detect abnormal mechanical or time characteristics of switchgear including circuit breakers at the first time. This capability significantly reduces the need for regular manual inspections, reduces unplanned power outages caused by faults, and also effectively controls manual maintenance costs. More importantly, the application of the present invention improves the efficiency of equipment use, ensures the safe and stable operation of the power system, and enhances the flexibility and reliability of the entire power grid architecture, which plays an extremely important role in promoting the healthy development of the power industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structural connection relationship of the system of the present invention;

[0033] Figure 2 Schematic diagram of the implementation process of the online detection method of the present invention;

[0034] Figure 3This is a schematic diagram of the feature extraction of the circuit breaker just-opening and just-closing points in the method of the present invention;

[0035] Figure 4 This is an example data diagram for calculating the closing time in the method of the present invention;

[0036] Figure 5 This is an example data diagram for calculating the opening time in the method of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] like Figure 1 As shown, a vacuum circuit breaker time characteristic detection system based on transient electrical signals includes the following components:

[0041] An opening and closing coil is used to control the opening and closing operation of the circuit breaker to be tested;

[0042] A voltage transformer, connected to the power supply side of the circuit breaker, is used to measure the voltage across the circuit breaker;

[0043] A current sensor is wrapped around the branch bus of the circuit breaker and is used to measure the current flowing through the circuit breaker;

[0044] A data acquisition instrument is used to receive the signals output by the opening and closing coils, the angular displacement sensor, the voltage transformer and the current sensor, and transmit the received signals to the host computer;

[0045] The host computer has a built-in feature extraction algorithm, which is used to analyze the relationship between the transient electrical signal and the time characteristic information generated by the circuit breaker during the opening and closing operations through the feature extraction algorithm, calibrate the circuit breaker's opening and closing points during each online detection of the circuit breaker, and obtain the time characteristic information of the current circuit breaker based on the calibration results, thereby realizing online detection of the circuit breaker's time characteristics.

[0046] In this embodiment, the opening and closing coil controls the opening and closing operation of the circuit breaker to be detected by outputting an opening and closing voltage signal.

[0047] In this embodiment, the transient electrical signal is divided into a transient voltage signal and a transient current signal. The transient voltage signal is measured by a voltage transformer, and the transient current signal is measured by a current sensor. The current sensor can be a Rogowski coil. On this basis, the data acquisition instrument will collect and receive transient voltage signals, transient current signals, and opening and closing voltage signals.

[0048] In this embodiment, the circuit breaker time characteristic information finally obtained by the upper computer through online detection includes the opening and closing points, the opening and closing time, the opening and closing speed, and the opening and closing stroke.

[0049] Example 2

[0050] Combination Figure 1 and Figure 2 Based on the example 1, this example introduces the implementation process of the vacuum circuit breaker time characteristic detection method corresponding to the system, which is described in detail as follows:

[0051] Step 1: Use a mechanical characteristic tester to obtain multiple sets of circuit breaker opening and closing time characteristic data through an angular displacement sensor for verification and comparative analysis;

[0052] Step 2: After the moving contact of the circuit breaker is connected to the ABC three-phase power supply channel of the mechanical characteristic tester, the angular displacement sensor is installed on the rotating shaft of the circuit breaker, so that under the action of the mechanical characteristic tester and the angular displacement sensor, the time characteristic information related to the stroke-time curve, the opening and closing points, the opening and closing time, the opening and closing speed, the opening and closing stroke, etc. of the circuit breaker are collected;

[0053] Step 3: Connect the high-voltage terminal of the voltage transformer to the power supply side of the circuit breaker, and connect the ground terminal of the voltage transformer to the ground wire of the power supply. The voltage measured by the voltage transformer is the voltage across the circuit breaker.

[0054] Step 4: Use a current sensor (specifically a Rogowski coil) to collect the current flowing through the circuit breaker. The Rogowski coil is directly wrapped around the branch bus of the circuit breaker for measurement. The measured current is the single-phase current of the circuit breaker.

[0055] Step 5: Here, an 8-channel data acquisition instrument is selected, and the sampling rate is set to 80Msps; Channel 1 and Channel 3 collect the opening and closing voltage signals; Channels 2, 5, and 7 collect transient voltage signals, and channels 4, 6, and 8 collect transient current signals; the data acquisition instrument transmits the collected signals to the host computer;

[0056] Step 6: Use an additional integrator, connect its input to the Rogowski coil, and its output to the data acquisition instrument;

[0057] Step 7: Change the operating conditions of the circuit breaker, collect and analyze the transient electrical signals generated when the circuit breaker performs opening and closing operations under different operating conditions, and then combine the travel-time curve measured offline in step 2 to obtain the corresponding relationship between the transient electrical signals during opening and closing operations and the time characteristics of the circuit breaker;

[0058] Step 8: Based on the corresponding relationship obtained in step 7, a feature extraction algorithm is used to extract features of transient electrical signals generated when the circuit breaker is opened and closed, so as to calibrate the opening and closing points of the circuit breaker, and obtain time characteristic information of the circuit breaker such as the opening and closing time, opening and closing speed, and opening and closing stroke;

[0059] Step nine: Perform error analysis on the circuit breaker time characteristic information obtained in step eight and the circuit breaker time characteristic information measured by the mechanical characteristic tester, so as to verify the effectiveness of the online detection system.

[0060] In this embodiment, Figure 3 As shown, when the opening / closing signal comes, the circuit breaker will perform the opening / closing operation. At this time, the voltage transformer and Rogowski coil in the system will collect the voltage and current signals at both ends of the circuit breaker, and the feature extraction algorithm will extract the features of the transient electrical signals in the collected signals.

[0061] In this embodiment, when the circuit breaker performs a closing operation, the feature extraction algorithm determines the time point at which the transient electrical signal appears last as the just-closing point of the circuit breaker; when the circuit breaker performs an opening operation, the feature extraction algorithm determines the time point at which the transient electrical signal appears earliest as the just-opening point of the circuit breaker. When the time characteristic of the circuit breaker is detected by the transient electrical signal, the transient voltage signal in the voltage measured by the voltage transformer is used as the main criterion, and the transient current signal in the current measured by the current sensor is used as the auxiliary criterion.

[0062] Figure 4 The data for calculating the closing time is given. Figure 5 The corresponding opening time is calculated. Figure 4 and Figure 5 In this embodiment, the calculation of the opening and closing time in the circuit breaker time characteristic information is introduced as follows:

[0063] When the host computer calculates the closing time of the current circuit breaker, the feature extraction algorithm obtains the triggering time point of the closing signal and the time point when the transient electrical signal appears last, and the difference between the two time points is obtained to obtain the closing time; when the host computer calculates the opening time of the current circuit breaker, the feature extraction algorithm obtains the triggering time point of the opening signal and the time point when the transient electrical signal appears earliest, and the difference between the two time points is obtained to obtain the opening time; the calculation formula is as follows:

[0064]

[0065] In the formula, t h is the time point when the transient electrical signal last appears during closing, t f It is the earliest time point when the transient electrical signal appears during opening. t1 and t2 are the triggering time points of the closing signal and the opening signal respectively.

[0066] Example 3

[0067] On the basis of Examples 1 and 2, in order to verify the online detection effect of the vacuum circuit breaker time characteristic detection system, this embodiment carried out 60 groups of online tests, and obtained 60 groups of circuit breaker mechanical characteristic information such as the opening and closing points, opening and closing time, opening and closing speed, and contact travel of the test.

[0068] Tables 1 and 2 are partial statistical tables of information on the time characteristics of the circuit breaker obtained by the system online detection, representing the online detection system's online detection of the circuit breaker's opening and closing points, opening and closing time, opening and closing speed, and opening and closing stroke.

[0069] Table 1 Statistics of some test closing information

[0070]

[0071]

[0072] Table 2 Statistics of some test tripping information

[0073]

[0074] After obtaining the above online detection data, the online detection data was compared and analyzed with the test data of the mechanical property tester, as shown in Table 3 and Table 4.

[0075] Table 3 Statistics of some closing errors

[0076]

[0077] Table 4 Statistics of some opening errors

[0078]

[0079]

[0080] The mean (ME) and variance (s) of the circuit breaker opening and closing time obtained from 60 groups of online tests were analyzed. 2 ), mean absolute deviation (MAD) and relative error (δ) analysis; respectively as follows:

[0081]

[0082] Among them, μ1 and μ2 are the average closing and opening times measured by the mechanical property tester; T 1n 、T 2n It is the closing and opening time measured by the online detection system; based on the above calculation formula, the calculation results are shown in Table 5 below.

[0083] Table 5 Analysis of online test results of opening and closing time

[0084] ME(ms) <![CDATA[s 2 (ms)]]> MAD(ms) δ(ms) Closing time 45.205 0.126 0.185 0.926％ Opening time 29.558 0.182 0.139 -0.944％

[0085] From the data analysis of Table 5, it can be seen that although the 60 sets of data have certain fluctuations, they are generally controlled within a certain range. The variance of the closing time is 0.126ms, and the variance of the opening time is 0.182ms, both within 0.2ms. It can be seen that the online detection method of the present invention has low volatility and high stability. The average absolute deviation of the closing time is 0.185ms, and the average absolute deviation of the opening time is 0.139ms. It can be seen that the detection results of the online detection system of the present invention have a small degree of discreteness and high detection accuracy. The relative error of the closing time of the 60 sets of data is 0.926%, and the relative error of the opening time is -0.944%, both of which are controlled within ±1%. The traditional mechanical property tester also has an error of ±1% in the measurement of the just-opening and just-closing points. It can be seen that the online detection system of the present invention has a high detection accuracy.

Claims

1. A vacuum circuit breaker time characteristic detection system based on transient electrical signals, characterized in that: The system includes the following components: An opening and closing coil is used to control the opening and closing operation of the circuit breaker to be tested; A voltage transformer, connected to the power supply side of the circuit breaker, is used to measure the voltage across the circuit breaker; A current sensor is wrapped around the branch bus of the circuit breaker and is used to measure the current flowing through the circuit breaker; A data acquisition instrument is used to receive the signals output by the opening and closing coils, the angular displacement sensor, the voltage transformer and the current sensor, and transmit the received signals to the host computer; The host computer has a built-in feature extraction algorithm, which is used to analyze the relationship between the transient electrical signal and the time characteristic information generated by the circuit breaker during the opening and closing operations through the feature extraction algorithm, calibrate the circuit breaker's opening and closing points during each online detection of the circuit breaker, and obtain the time characteristic information of the current circuit breaker based on the calibration results, thereby realizing online detection of the circuit breaker's time characteristics.

2. The vacuum circuit breaker time characteristic detection system according to claim 1, characterized in that: The opening and closing coil controls the opening and closing operation of the circuit breaker to be detected by outputting the opening and closing voltage signal.

3. The vacuum circuit breaker time characteristic detection system according to claim 2, characterized in that: When the circuit breaker is opening and closing, the voltage measured by the voltage transformer includes a transient voltage signal, and the current sensor uses a Rogowski coil, and the current measured by the current transformer includes a transient current signal; The data acquisition instrument collects and receives transient voltage signals, transient current signals, and opening and closing voltage signals through multiple preset channels under preset sampling rate conditions.

4. The vacuum circuit breaker time characteristic detection system according to claim 1, characterized in that: The host computer is also used to collect the transient electrical signals generated during the circuit breaker opening and closing operations under different circuit breaker operating conditions, and conduct comparative analysis based on the time characteristic information obtained from offline testing to obtain the relationship between the transient electrical signals and the corresponding time characteristic information, and determine the feature extraction algorithm.

5. The vacuum circuit breaker time characteristic detection system according to claim 4, characterized in that: The time characteristic information includes the opening and closing points, opening and closing time, opening and closing speed, and opening and closing travel.

6. A method for detecting time characteristics of a vacuum circuit breaker based on transient electrical signals, characterized in that: The method comprises the following steps: S1. Use an angular displacement sensor to collect the travel-time curve and time characteristic information of the circuit breaker and transmit them to a mechanical characteristic tester to form offline comparison data based on the time characteristic information; S2. When the circuit breaker is online, the voltage across the circuit breaker is measured by a voltage transformer, and the current flowing through the circuit breaker is measured by a current sensor; S3, the data acquisition instrument collects the output signals of the opening and closing coils, the voltage transformer and the current sensor and transmits them to the host computer; S4, changing the operating conditions of the circuit breaker, respectively collecting corresponding signals of the circuit breaker under different operating conditions, and combining the travel-time curve obtained in step S1 to determine the corresponding relationship between the transient electrical signal generated by the opening and closing operation and the time characteristic information of the circuit breaker; S5. When the circuit breaker is online, the transient electrical signal generated by the circuit breaker during the opening and closing operation is extracted through a feature extraction algorithm. According to the corresponding relationship determined in step S4, the opening and closing points of the circuit breaker are calibrated, and the time characteristic information of the current circuit breaker is obtained by the host computer.

7. The method for detecting time characteristics of a vacuum circuit breaker according to claim 6, characterized in that: In step S5, when the circuit breaker is closed, the feature extraction algorithm determines the time point when the transient electrical signal last appears as the circuit breaker's just-closing point; when the circuit breaker is opened, the feature extraction algorithm determines the time point when the transient electrical signal first appears as the circuit breaker's just-opening point.

8. The method for detecting time characteristics of a vacuum circuit breaker according to claim 7, characterized in that: When the time characteristic detection of the circuit breaker is performed through the transient electrical signal, the transient voltage signal in the voltage measured by the voltage transformer is used as the main criterion, and the transient current signal in the current measured by the current sensor is used as the auxiliary criterion.

9. The method for detecting time characteristics of a vacuum circuit breaker according to claim 7, characterized in that: When the host computer calculates the closing time of the current circuit breaker, the feature extraction algorithm obtains the triggering time point of the closing signal and the last time point of the transient electrical signal, and the difference between the two time points is used to obtain the closing time; The calculation formula is as follows: T 合闸时间 =t h -t1 In the formula, t h is the time point when the transient electrical signal last appears during closing, and t1 is the triggering time point of the closing voltage signal.

10. The method for detecting time characteristics of a vacuum circuit breaker according to claim 7, characterized in that: When the host computer calculates the opening time of the current circuit breaker, the feature extraction algorithm obtains the triggering time point of the opening signal and the earliest time point of the transient electrical signal, and the difference between the two time points is used to obtain the opening time; The calculation formula is as follows: T 分闸时间 =t f -t2 In the formula, t f is the earliest time point when the transient electrical signal appears during opening, and t2 is the triggering time point of the opening voltage signal.

Images