Automatic phase correction method and spare power automatic switching device

Abstract

The invention discloses an automatic phase correction method and a spare power automatic switching device, and the method comprises the following steps: synchronously collecting three-phase voltage signals of a first bus and a second bus through an electrical quantity sampling unit, carrying out the frequency domain transformation of the collected signals through a processing unit, extracting the amplitude and phase parameters of a power frequency component, and carrying out the phase correction of the power frequency component; when each phase voltage of the two sections of buses continuously exceeds a preset threshold value and the duration time is greater than or equal to 2 seconds, starting a phase correction process, judging whether a line is abnormal or not, outputting a corresponding signal, putting the spare power automatic switching device into work after the phase correction is successful, a mutual inductance coil of which the input side is mutually connected with the output ends of the first bus and the second bus, and a filter, according to the voltage transformer secondary phase correction device, automatic measurement of secondary phase correction of the voltage transformer is achieved, low efficiency and high error rate of manual operation are avoided, and reliability of power transmission and operation of transformer station equipment is improved.

Description

Technical Field

[0001] This invention relates to the field of phase calibration monitoring, and in particular to an automatic phase calibration method and an automatic switching device. Background Technology

[0002] For power distribution networks, if there is a fixed phase difference or amplitude difference between the three phases, a huge current will be generated in the circuit when two power lines are connected in parallel or looped. This can easily cause abnormal operation of equipment and damage related electrical equipment. Therefore, secondary phase calibration of voltage transformers is a necessary test item after the equipment is energized in the new, modified, or expanded projects of distribution substations. Currently, the secondary phase calibration equipment for voltage transformers mainly uses multimeters and phase sequence meters. The process is cumbersome, has a high error rate, and low efficiency, and cannot achieve automated measurement. Existing technology uses multimeters and phase sequence meters to perform secondary phase calibration measurements for voltage transformers. The process is cumbersome, has a high error rate, and low efficiency, and cannot achieve automated measurement. It cannot effectively solve the problem that when two power lines are connected in parallel or looped, if there is a fixed phase difference or amplitude difference between the three phases, a huge current will be generated in the circuit, which can easily cause abnormal operation of equipment and damage related electrical equipment. Summary of the Invention

[0003] Therefore, the technical problem to be solved by this invention is that the process is cumbersome, the error rate is high, the efficiency is low, and it is impossible to achieve automated measurement.

[0004] The above-mentioned technical problems are solved by the following technical solution: This invention proposes an automatic phase correction method and a backup automatic transfer device, which includes,

[0005] The three-phase voltage signals of the first bus and the second bus are synchronously acquired through the electrical quantity sampling unit.

[0006] The processing unit performs frequency domain transformation on the acquired signal to extract the amplitude and phase parameters of the power frequency component;

[0007] When the phase voltage of each phase of the two busbars continuously exceeds the preset threshold and the duration is ≥2 seconds, the phase correction process is started to determine whether there is an abnormality in the line and output the corresponding signal.

[0008] After the alignment was successfully completed, the automatic switching device was put into operation.

[0009] In a preferred embodiment of the automatic phase correction method of the present invention: the voltage preset threshold is ≥10V, the phase parameters include the phase correction angle difference and the phase correction voltage difference, wherein the phase correction angle difference threshold is ≤15°, the phase correction voltage difference threshold is ≤8V, and the electrical quantity sampling unit accuracy level is 0.2.

[0010] In a preferred embodiment of the automatic phase correction method of the present invention: the phase correction process is embedded with phase correction judgment logic, the judgment logic including: if the pressure difference between the three corresponding phases between the first bus and the second bus is lower than the set phase correction pressure difference threshold, and the angle difference between the three corresponding phases is less than the set phase correction angle difference threshold for more than 2 seconds, the phase correction is judged to be correct and a phase correction correct signal is output; if the pressure difference between the three corresponding phases between the first bus and the second bus is higher than the set phase correction pressure difference threshold, and the angle difference between the three corresponding phases is greater than the set phase correction angle difference threshold for more than 2 seconds, the phase correction is judged to be failed and a phase correction abnormal signal is output.

[0011] In a preferred embodiment of the automatic phase correction method of the present invention: the phase correction judgment logic further includes: if the phase sequence of the first bus and the second bus is abnormally alarmed, that is, there is a two-phase or three-phase power supply error or a three-phase wiring error of the electrical quantity sampling unit.

[0012] In a preferred embodiment of the automatic phase correction method of the present invention: the wiring error judgment logic includes: if the voltage difference between the three phases of the first bus and the second bus is lower than the set phase correction voltage difference threshold, and the first phase angle difference between the first bus and the second bus is less than the set phase correction angle difference threshold, and the second phase angle difference between the second phase of the first bus and the third phase of the second bus is less than the set phase correction angle difference threshold, and the third phase angle difference between the third phase of the first bus and the second phase of the second bus is less than the set phase correction angle difference threshold, the output signal is: a wiring error has occurred on one side of the second or third phase of the first bus and the second bus.

[0013] In a preferred embodiment of the automatic phase correction method of the present invention: the wiring error judgment logic further includes: phase sequence error judgment logic: collecting negative sequence voltage information of the second and third phases of the first bus and the second bus, comparing the collected information with a preset threshold, and judging the bus with abnormal sequence. The preset threshold for negative sequence voltage is 8V.

[0014] In a preferred embodiment of the automatic phase correction method of the present invention: if a power failure occurs on the first bus or the second bus, the automatic transfer switch is activated to trip the faulty power supply, close the switch, and restore power supply.

[0015] An automatic switching device includes,

[0016] Mutual inductance coils, the input side of which is connected to the output terminals of the first busbar and the second busbar;

[0017] A filter is provided on the output side of the mutual inductance coil.

[0018] In a preferred embodiment of the automatic switching device of the present invention: the automatic switching device is provided with a control unit, and the control unit is provided with a human-machine interface.

[0019] In a preferred embodiment of the automatic switching device of the present invention: the control unit is further provided with an output unit and an external interface.

[0020] The beneficial effects of this invention are as follows: it realizes the automated measurement of secondary phase correction of voltage transformers, avoids the low efficiency and high error rate of manual operation, improves the reliability of power supply and operation of substation equipment, and effectively solves the problem that when two power lines are connected in parallel or looped, if there is a fixed phase difference or amplitude difference between the three phases, a huge current will be generated in the circuit, which can easily cause abnormal operation of equipment and damage to related electrical equipment. By collecting electrical quantities such as voltage and current between the two power lines, and using algorithms to analyze the electrical quantities, the phase difference and amplitude difference between the three phases are automatically identified, thereby realizing automatic phase correction, avoiding the low efficiency and high error rate of manual operation. Adding automatic phase correction function to the automatic transfer switch does not require additional equipment or re-laying of cables, reducing investment costs and making it more conducive to the safe and stable operation of the power grid. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein:

[0022] Figure 1 A schematic diagram of the circuit acquisition structure of the present invention is shown;

[0023] Figure 2 A schematic diagram of the control device structure of the present invention is shown;

[0024] Figure 3 A schematic diagram of the judgment logic structure of the present invention is shown. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terminology used in this specification should not be construed as simple names, but rather based on the meaning of the terms and the overall description of the invention.

[0027] Reference Figure 3This embodiment provides an automatic phase correction method. The method involves synchronously acquiring the three-phase voltage signals of the first busbar 10 and the second busbar 20 via an electrical quantity sampling unit. The processing unit performs frequency domain transformation on the acquired signals, extracting the amplitude and phase parameters of the power frequency component. When the phase voltage of each phase of the two busbars continuously exceeds a preset threshold for a duration ≥ 2 seconds, the phase correction process is initiated to determine if there is an abnormality in the line and outputs a corresponding signal. After successful phase correction, the automatic transfer switch is activated. The preset voltage threshold is ≥ 10V. The phase parameters include the phase correction angle difference and the phase correction voltage difference, where the threshold for the phase correction angle difference is ≤ 15° and the threshold for the phase correction voltage difference is ≤ 15°. For voltages ≤8V, the electrical quantity sampling unit has an accuracy class of 0.2. The phase calibration process includes embedded phase calibration judgment logic. The judgment logic includes: if the voltage difference between the three corresponding phases between the first bus 10 and the second bus 20 is lower than the set phase calibration voltage difference threshold, and the angle difference between the three corresponding phases is less than the set phase calibration angle difference threshold for more than 2 seconds, the phase calibration is judged to be correct, and a phase calibration correct signal is output. If the voltage difference between the three corresponding phases between the first bus 10 and the second bus 20 is higher than the set phase calibration voltage difference threshold, and the angle difference between the three corresponding phases is greater than the set phase calibration angle difference threshold for more than 2 seconds, the phase calibration is judged to be failed, and a phase calibration abnormal signal is output.

[0028] The wiring error judgment logic includes: if the voltage difference between the three phases of the first busbar 10 and the second busbar 20 is lower than the set phase voltage difference threshold, and the first phase angle difference between the first busbar 10 and the second busbar 20 is less than the set phase angle difference threshold, and the second phase angle difference between the first busbar 10 and the second phase angle difference between the second phase and the second phase angle difference between the second phase and the second phase angle difference between the first busbar 10 and the second phase angle difference between the second phase and the second phase angle difference between the first busbar 10 and the second busbar 20 is less than the set phase angle difference threshold, the output signal is: a wiring error has occurred on one side of the second or third phase of the first busbar 10 and the second busbar 20. The wiring error judgment logic also includes: phase sequence error judgment logic: collect the negative sequence voltage information of the second and third phases of the first busbar 10 and the second busbar 20, compare the collected information with the preset threshold, and judge the abnormal busbar sequence. The preset threshold for negative sequence voltage is 8V. If a power failure occurs in the first busbar 10 or the second busbar 20, the automatic transfer switch is activated to trip the faulty power supply, close the switch, and restore power supply.

[0029] refer to Figure 1 and Figure 2 This embodiment provides a backup automatic transfer device, a mutual inductor coil 30, whose input side is connected to the output ends of the first bus 10 and the second bus 20, a filter 41, which is disposed on the output side of the mutual inductor coil 30, and a control unit 40, which is provided with a human-machine interface 42, an output unit 43 and an external interface 44. The above-mentioned device is installed on the backup automatic transfer device to cooperate with the device to perform power supply work, thereby improving the reliability of power supply and operation of substation equipment.

[0030] reference Figures 1 to 3The phase sequence judgment logic also includes the following: If an alarm is triggered for an abnormal phase sequence of the first busbar 10 and the second busbar 20, indicating a two-phase or three-phase power supply error or a three-phase wiring error in the electrical quantity sampling unit, and if the voltage difference between the first, second, and third phases of the first busbar 10 and the second busbar 20 is lower than the set phase sequence voltage difference threshold, the angle difference between the first phase of the first busbar 10 and the second busbar 20 is less than the set phase sequence angle difference threshold, the angle difference between the second phase of the first busbar 10 and the third phase of the second busbar 20 is less than the set phase sequence angle difference threshold, and the angle difference between the third phase of the first busbar 10 and the second phase of the second busbar 20 is less than the set phase sequence angle difference threshold, it indicates that one side of the second or third phase of the first busbar 10 and the second busbar 20 is reversed. Then, by using the negative sequence voltage, it can be determined which busbar has an abnormal phase sequence. At this time, the negative sequence voltage calculated by the three-phase voltage of the first busbar 10 will exceed the negative sequence voltage threshold, and the device determines that the second or third phase of the first busbar 10 is reversed. Phase sequence error; at this time, the negative sequence voltage calculated by the three-phase voltage of the second bus 20 will exceed the negative sequence voltage threshold. The device determines that the second and third phase sequences of the second bus 20 are incorrect. If the voltage difference between the first, second, and third phases of the first bus 10 and the second bus 20 is lower than the set phase correction voltage difference threshold, the angle difference between the first phase of the first bus 10 and the second phase of the second bus 20 is less than the set phase correction angle difference threshold, the angle difference between the second phase of the first bus 10 and the first phase of the second bus 20 is less than the set phase correction angle difference threshold, and the angle difference between the third phase of the first bus 10 and the second bus 20 is less than the set phase correction angle difference threshold, it means that one side of the first phase and the second phase of the first bus 10 and the second bus 20 is reversed. By using the negative sequence voltage, it can be determined which bus has an abnormal phase sequence. At this time, the negative sequence voltage calculated by the three-phase voltage of the first bus 10 will exceed the negative sequence voltage threshold. The device determines that the first and second phase sequences of the first bus 10 are incorrect. At this time, the negative sequence voltage calculated by the three-phase voltage of the second bus 20 will exceed the negative sequence voltage threshold. The device determines that the first and second phase sequences of the second bus 20 are incorrect. If the voltage difference between the first, second, and third phases of the first bus 10 and the second bus 20 is lower than the set phase correction voltage difference threshold, the angle difference between the first phase of the first bus 10 and the third phase of the second bus 20 is less than the set phase correction angle difference threshold, the angle difference between the second phase of the first bus 10 and the second bus 20 is less than the set phase correction angle difference threshold, and the angle difference between the third phase of the first bus 10 and the first phase of the second bus 20 is less than the set phase correction angle difference threshold, it indicates that one side of the first and third phases of the first bus 10 and the second bus 20 is reversed. By using the negative sequence voltage, it can be determined which bus has an abnormal phase sequence. At this time, the negative sequence voltage calculated by the three-phase voltage of the first bus 10 will exceed the negative sequence voltage threshold. The device determines that the first and third phase sequences of the first bus 10 are incorrect.At this time, the negative sequence voltage calculated by the three-phase voltage of the second bus 20 will exceed the negative sequence voltage threshold, and the device will determine that the first and third phase sequences of the second bus 20 are incorrect.

[0031] After the phase calibration function is activated, if the three-phase voltages of the first busbar 10 and the second busbar 20 are all greater than 10V, the automatic phase calibration function will be automatically started. If the voltage difference between the first phase, the second phase, and the third phase between the first busbar 10 and the second busbar 20 is greater than the set phase calibration voltage difference threshold, after a 2-second delay, the device will set a phase calibration failure flag and light an alarm light. If the voltage difference between the first busbar 10 and the second busbar 20 is abnormal, an alarm will be triggered.

[0032] During operation, the three-phase voltage signals of the first busbar 10 and the second busbar 20 are synchronously acquired through the electrical quantity sampling unit. The processing unit performs frequency domain transformation on the acquired signals, extracting the amplitude and phase parameters of the power frequency component. When the phase voltage of each phase of the two busbars continuously exceeds the preset threshold for a duration of ≥2 seconds, the phase correction process is initiated to determine if there is an abnormality in the line and outputs the corresponding signal. After successful phase correction, the automatic transfer switch is activated. After the phase correction function is activated, if the three-phase voltages of the first busbar 10 and the second busbar 20 are both greater than 10V, the automatic phase correction function is automatically activated. If the first phase voltage of the first busbar 10 and the second busbar 20 is greater than 10V, the automatic phase correction function is activated. If the voltage difference between the first phase, the second phase, and the third phase is greater than the set voltage difference threshold for phase calibration, after a 2-second delay, the device will set a phase calibration failure flag and light an alarm. If the voltage difference between the first bus 10 and the second bus 20 is abnormal, an alarm will be triggered. After the phase calibration function is activated, if the three-phase voltages of the first bus 10 and the second bus 20 are all greater than 10V, the automatic phase calibration function will be automatically activated. If the angle difference between the first phase, the second phase, and the third phase between the first bus 10 and the second bus 20 is greater than the set voltage difference threshold for phase calibration, after a 2-second delay, the device will set a phase calibration failure flag and light an alarm. If the angle difference between the first bus 10 and the second bus 20 is abnormal, an alarm will be triggered.

[0033] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. An automatic phase correction method, characterized by: The method comprises the following steps, Synchronously collecting three-phase voltage signals of the first bus (10) and the second bus (20) by an electrical quantity sampling unit; The processing unit performs frequency domain transformation processing on the collected signals to extract the amplitude and phase parameters of the power frequency component; When the voltage of each phase of the two bus sections continuously exceeds the preset threshold value and the duration is greater than or equal to 2 seconds, a phase correction process is started, whether the line is abnormal is judged, and a corresponding signal is output; After the phase correction is successful, the backup power supply device is put into operation.

2. The automatic phasing method of claim 1, wherein: The voltage preset threshold value is greater than or equal to 10V, the phase parameters include a phase correction angle difference and a phase correction voltage difference, the phase correction angle difference threshold value is less than or equal to 15°, the phase correction voltage difference threshold value is less than or equal to 8V, and the precision level of the electrical quantity sampling unit is 0.

2.

3. The automatic phasing method of claim 2, wherein: The phase correction process is embedded with phase correction judgment logic. The judgment logic comprises: if the voltage difference between the first bus (10) and the second bus (20) is lower than the set phase correction voltage difference threshold value, and the angle difference of the three phases is less than the set phase correction angle difference threshold value for more than 2 seconds, it is judged that the phase correction is correct, and a phase correction correct signal is output; If the voltage difference between the first bus (10) and the second bus (20) is higher than the set phase correction voltage difference threshold value, and the angle difference of the three phases is greater than the set phase correction angle difference threshold value for more than 2 seconds, it is judged that the phase correction fails, and a phase correction abnormal signal is output.

4. The automatic phasing method according to claim 3, characterized in that: The phase correction judgment logic further comprises: If the phase sequence of the first bus (10) and the second bus (20) is abnormal, that is, the bus has two-phase or three-phase power supply error or three-phase connection error of the electrical quantity sampling unit.

5. The automatic phasing method of claim 4, wherein: The connection error judgment logic comprises: If the voltage difference between the first bus (10) and the second bus (20) is lower than the set phase correction voltage difference threshold value, and the angle difference of the first phase of the first bus (10) and the second bus (20) is less than the set phase correction angle difference threshold value, and the angle difference of the second phase of the first bus (10) and the third phase of the second bus (20) is less than the set phase correction angle difference threshold value, and the angle difference of the third phase of the first bus (10) and the second phase of the second bus (20) is less than the set phase correction angle difference threshold value; The output signal is that one side of the second and third phases of the first bus (10) and the second bus (20) has connection error.

6. The automatic phasing method according to claim 5, characterized in that: The connection error judgment logic further comprises: The phase sequence error judgment logic: the second and third phase negative sequence voltage information of the first bus (10) and the second bus (20) is collected, and the collected information is compared with the preset threshold value to judge the abnormal bus, and the negative sequence voltage preset threshold value is 8V.

7. The automatic phasing method as claimed in claim 1, wherein: If the first bus (10) or the second bus (20) has power failure, the backup power supply device starts to trip the faulty power supply, closes the switch, and restores power supply.

8. A device for backup power supply automatic throw-in, such as the automatic phase adjustment method of any one of claims 1 to 7, characterized in that: It comprises, A mutual inductor (30) having an input side connected to the output ends of the first bus (10) and the second bus (20); A filter (41) arranged at the output side of the mutual inductor (30).

9. The device according to claim 8, characterized in that: The output end of the filter (41) is provided with a control unit (40), and a man-machine interface (42) is arranged on the control unit (40).

10. The device according to claim 9, characterized in that: The control unit (40) is further provided with an output unit (43) and an external interface (44).

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