A method and device for synchronizing wave recording transient data

Abstract

The invention discloses a method for synchronizing transient data of recording. By establishing a fault component phase judgment process, the fault component is subjected to fault phase judgment to determine the fault current phase difference; a mutation threshold is set according to the rated value of the fault current channel; traversal is performed from the recording start point, and the instantaneous value difference between the current point and the point two cycles ago is calculated. When the instantaneous value difference is greater than the mutation threshold, the current point is recorded as a transient data mutation point; a clock deviation threshold is set, and the time difference of all transient data mutation points is compared. If the time difference range is less than the clock deviation threshold, the mutation point is determined to be a synchronization point; the angle of each transient data mutation point is calculated, and the angle difference of all transient data mutation points is compared. If the angle difference range is less than the threshold, the mutation point is determined to be a synchronization point; if the clock and the angle cannot determine the synchronization point, the synchronization point is determined using the angle difference compensation, that is, the number of offset points is obtained according to the angle difference calculation, and the new synchronization point is obtained after the offset point is moved according to the mutation point. Through the above process, it is not strictly dependent on the external clock timing, and the recording transient data can be synchronized according to the change trend of the waveform.

Description

Technical Field

[0001] The invention relates to the field of power system automation, and in particular to a method and a device for synchronizing wave recording transient data. Background Art

[0002] When a power system fails, secondary equipment in the substation, including protection devices and wave recording devices, will trigger transient wave recording to record grid data before and after the failure. With the improvement of intelligent analysis of grid faults, data analysis of a single device no longer meets the needs of users. Joint analysis of multi-device data across bays and substations, such as homologous source comparison and double-end ranging, is becoming increasingly important.

[0003] Synchronization of recorded data, especially transient data, is an important step in joint analysis. Only after multiple data are synchronized, joint analysis is possible. In existing technologies, synchronization is generally performed through the clock timestamps of the data itself, that is, the points with the same timestamp of multiple data files are selected as the synchronization starting point. This synchronization method often requires strict time synchronization of the device. If the device is not synchronized, or there is a deviation in the synchronization between the clock devices, there will be errors in the timestamps between the recorded transient data, affecting the data synchronization effect and subsequent joint analysis. Summary of the invention

[0004] In order to realize the joint analysis of recorded transient data, the present invention provides a recorded transient data synchronization method and device.

[0005] A method and device for synchronizing waveform transient data, comprising the following steps: Step 1: Phase determination of the faulty component, obtaining the fault component of the component line current, the positive sequence current and the zero sequence fault component. If the zero sequence fault component is greater than 0.1 times the positive sequence current, it is determined to be a single-phase grounding fault. Otherwise, the phase-to-phase or phase-to-phase grounding fault is determined according to the line current fault component, and the fault current phase is determined. Step 2: Determine the mutation point of the recorded transient data of the fault channel according to the phase judgment result, and set the mutation threshold according to the rated value of the fault current channel. The mutation threshold is generally 0.1 times the rated value. Start traversing from the starting point of the recording, calculate the difference between the instantaneous value of the current point and the point two cycles ago, and when the difference is greater than the mutation threshold, record the current point as the transient data mutation point; Step 3: determine whether the mutation point meets the synchronization condition in time, that is, set the clock deviation threshold, compare the time difference of the mutation points of all transient data, and if the time difference range is less than the threshold, determine that the mutation point is a synchronization point; Step 4: If the synchronization point cannot be determined through step 3, then set an angle deviation threshold, calculate the angle of each transient data mutation point, compare the angle differences of all transient data mutation points, and if the angle difference range is less than the angle deviation threshold, determine that the mutation point is a synchronization point; Step 5: If the synchronization point cannot be determined by the clock and the angle, the synchronization point is determined using the angle difference compensation, that is, the number of offset points is obtained according to the angle difference calculation, and the new synchronization point is obtained after the offset point is moved according to the mutation point.

[0006] The present invention has the following advantages: it does not strictly rely on external clock synchronization, and can synchronize the recorded transient data according to the changing trend of the waveform. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0008] Figure 1 It is the synchronization process of recording transient data;

[0009] Figure 2 Confirm the process for synchronization point. DETAILED DESCRIPTION

[0010] The present invention provides a method and device for synchronizing waveform transient data, which can realize reliable acquisition of joint analysis synchronization points.

[0011] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0012] like Figure 1 As shown, the method described in the present invention includes the following process: 1. Fault component phase determination process, as shown in S1, is used to screen the fault channel. The sudden change of the fault channel is obvious, so the fault channel is generally used to confirm the synchronization point. The fault channel phase is determined by using the component line current fault component, positive sequence current and zero sequence fault component; 2. Fault mutation point judgment process, as shown in S2, this process is used to select the mutation point of the fault channel. Start from the recording start point of the channel and use the period instantaneous value difference to obtain the mutation point; 3. Synchronization point confirmation process, as shown in S3, is used to confirm the transient synchronization point. Taking the mutation point as the reference point, the transient data synchronization point is obtained by using the time difference and angle difference method.

[0013] like Figure 2 As shown, the synchronization point confirmation method of the present invention includes the following process: 1. The mutation point time difference judgment process, as shown in S301 and S302, extracts the time of the mutation point, calculates the mutation point time difference ΔT of the transient data mutation point, and when the time difference ΔT is less than the set threshold T h When , it means that the transient data is strictly synchronized and the data synchronization point is found, otherwise it enters the angle difference judgment process; 2. The process of judging the angle difference of the mutation point, as shown in S303 and S304, is used to judge the angle difference of the mutation point. The angle value and the angle difference ΔA of the mutation point are obtained by using the full-wave Fourier algorithm. When the angle difference ΔA is less than the set threshold value A h When , it can be said that the transient data mutation points are basically synchronized, otherwise it enters the angle difference compensation process; 3. Angle difference compensation judgment process, as shown in S305, this process is used to determine the synchronization point by compensation method when the phase angle difference fails to judge the synchronization point. The number of compensation points is equal to (angle difference ΔA / 360)*(sampling rate / frequency). The new synchronization point is obtained after moving the compensation points according to the mutation point.

[0014] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method and device for synchronizing waveform transient data, characterized in that: The method comprises the following steps: Step 1, establish a fault component phase judgment process, obtain the line current fault component, positive sequence current and zero sequence fault component of the component, and judge whether it is a single-phase grounding fault by whether the zero sequence fault component is greater than 0.1 times the positive sequence current. According to the line current fault component, the phase-to-phase or phase-to-phase grounding fault is judged to determine the fault current phase difference; Step 2: Determine the mutation point of all recorded transient data: set the mutation threshold according to the rated value of the fault current channel; start traversing from the starting point of the recording, calculate the instantaneous value difference between the current point and the point two cycles ago, and when the instantaneous value difference is greater than the mutation threshold, record the current point as the transient data mutation point; Step 3: determine whether the mutation point meets the synchronization condition in time, that is, set the clock deviation threshold, compare the time difference of the mutation points of all transient data, and if the time difference range is less than the threshold, determine that the mutation point is a synchronization point; Step 4: If the synchronization point cannot be determined through step 3, then set an angle deviation threshold, calculate the angle of each transient data mutation point, and compare the angle differences of all transient data mutation points. If the angle difference range is less than the angle deviation threshold, the mutation point is determined to be a synchronization point. Step 5: If the synchronization point cannot be determined by the clock and the angle, the synchronization point is determined using the angle difference compensation, that is, the number of offset points is obtained according to the angle difference calculation, and the new synchronization point is obtained after the offset point is moved according to the mutation point.

2. A method for synchronizing recorded transient data according to claim 1, characterized in that: In step 1, the fault phase judgment method is used to select the fault current phase, and then determine the channel that needs to be synchronized.

3. A method for synchronizing recorded transient data according to claim 1, characterized in that: In step 2, traverse from the starting position of the recording and obtain the mutation point by using the periodic instantaneous value.

4. A method for synchronizing recorded transient data according to claim 1, characterized in that: Contains the following modules: 1). Use the clock deviation judgment method to determine whether the mutation point is a synchronization point; 2). Use the angle deviation judgment method to determine whether the mutation point is a synchronization point; 3). Use the angle difference compensation method to determine the synchronization point. The number of compensation points is equal to (angle difference / 360)*(sampling rate / frequency).

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