CN-122026275-A - Main transformer high-voltage side interphase backup protection device and method

CN122026275ACN 122026275 ACN122026275 ACN 122026275ACN-122026275-A

Abstract

The invention discloses a main transformer high-voltage side inter-phase backup protection device and method, and relates to the technical field of relay protection of power systems. The device outputs two paths of homologous digital signals through the signal acquisition module, so that the protection DSP board and the starting DSP board which are mutually independent in the data processing module can perform parallel processing, the protection DSP board performs composite voltage locking and overcurrent protection logic, the starting DSP board performs starting condition judgment, and the outlet execution module only performs isolation action when the protection action logic signal and the power supply opening signal are received at the same time and the logic locking circuit does not output a locking signal. The invention also supports the functions of flexible selection of high and low voltage side back pressure, PT disconnection self-adaptive processing and direction discrimination, doubly improves the protection reliability from the hardware and logic level, solves the problems of insufficient sensitivity, weak anti-interference capability and poor configuration flexibility of the traditional device, and is suitable for the alternate backup protection scenes of various transformer stations.

Inventors

YAO LIANG
YUAN HONGPING
LIU PAN
YANG ZHANGBIN
MA ZHIZHONG
Yu Zhenchang
CHEN ZIYI
HOU XIANDONG
MENG XIANYU

Assignees

中国三峡建工(集团)有限公司
南京南瑞继保工程技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (10)

1. The utility model provides a main high-voltage side alternate backup protection device which characterized in that includes: a signal acquisition module (100) for acquiring the analog signal of the electric quantity of the transformer and outputting two homologous digital signals, and The data processing module (200) comprises two mutually independent DSP boards, the two DSP boards respectively receive one path of the homologous digital signals, one path of the two DSP boards executes protection logic calculation and outputs protection action logic signals, and the other path of the two paths of the homologous digital signals execute starting condition judgment and output power supply open signals; and the outlet execution module (300) is respectively connected with the two DSP boards and executes isolation action only when the protection action logic signal and the power supply open signal are received at the same time.
2. The main transformer high-voltage side alternate backup protection device according to claim 1, wherein, The signal acquisition module (100) comprises an analog input unit (101), a low-pass filtering unit (102) and an A/D conversion unit (103); the analog input unit (101) is used for collecting an electric analog signal of the transformer, the output end of the analog input unit is connected with two paths of independent analog processing channels, and each path of channel comprises a low-pass filtering unit (102) and an A/D conversion unit (103) which are sequentially connected and used for filtering high-frequency interference in the signal, converting the high-frequency interference into digital signals and respectively outputting the digital signals to the two DSP boards.
3. The main transformer high-voltage side interphase backup protection device according to claim 2, wherein the electric quantity analog signal collected by the analog quantity input unit (101) comprises an alternating voltage signal and an alternating current signal; The alternating current signal comprises alternating voltage of a high-voltage side and a low-voltage side of the main transformer, negative sequence voltage and zero sequence voltage, and the alternating current signal comprises backup current of the high-voltage side and backup current of the low-voltage side.
4. A main transformer high-voltage side phase-to-phase backup protection device according to claim 1 or 3, characterized in that the device further comprises: The switching value input module (400) is used for collecting external switching signals, and transmitting the external switching signals to the data processing module (200) after optical isolation, wherein the external switching signals comprise a breaker position signal, a PT wire breaking signal and a protective pressing plate switching signal.
5. The main transformer high-voltage side inter-phase backup protection device according to claim 4, wherein the two DSP boards of the data processing module (200) are a protection DSP board (201) and a start DSP board (202), respectively; The protection DSP board (201) calculates negative sequence voltage and low voltage based on alternating voltage signals to form a composite voltage locking criterion, calculates a three-phase current maximum value based on alternating current signals to form an overcurrent criterion, combines external signals acquired by the switching value input module (400) to output protection action logic signals, and the starting DSP (202) board is used for realizing starting element detection and opening a positive power supply of the outlet execution module (300) when starting conditions are met.
6. The main transformer high-voltage side interphase backup protection device according to claim 5, wherein the composite voltage blocking criterion is satisfied that the negative sequence voltage is greater than a negative sequence voltage fixed value or the interphase low voltage is less than a low voltage fixed value.
7. The main transformer high-voltage side interphase backup protection device according to claim 5, wherein the over-current criterion is satisfied that a maximum value of three-phase current is greater than an over-current constant value.
8. The main transformer high-voltage side inter-phase backup protection device according to claim 5, 6 or 7, wherein a logic locking circuit (203) is integrated in the data processing module (200), the logic locking circuit (203) is respectively connected with the protection DSP board (201) and the starting DSP board (202) in a bidirectional manner, and is used for acquiring working states and mutual detection data of the two DSP boards in real time, outputting a locking signal when any DSP board fails or the data is inconsistent, and the outlet execution module (300) executes an isolation action only when a protection action logic signal and a power supply opening signal are simultaneously received and no locking signal is received.
9. The method for protecting the phase backup of the high-voltage side of the main transformer, which is applied to the device as claimed in any one of claims 1 to 8, is characterized by comprising the following steps: The signal acquisition module (100) acquires alternating current and voltage signals in real time, and respectively transmits the alternating current and voltage signals to the starting DSP board (202) and the protecting DSP board (201) after filtering and A/D conversion; The overcurrent starting element of the starting DSP board (202) detects the maximum value of the three-phase current in real time, and when the maximum value is larger than the setting value of the overcurrent current, the starting element acts to open the positive power supply at the outlet; The protection DSP board (201) calculates negative sequence voltage and interphase low voltage based on alternating voltage signals and judges whether a composite voltage locking criterion is met or not; the method comprises the steps of calculating the maximum value of three-phase current based on an alternating current signal, judging whether an overcurrent criterion is met, receiving a PT disconnection signal and a protection pressing plate switching signal transmitted in real time by a switching value input module (400), and judging the effectiveness; when the composite voltage locking criterion and the overcurrent criterion are met, the protection pressing plate acquired by the switching value input module (400) is in an input state, the PT disconnection signal is in a normal state, and all conditions that the starting DSP board (202) has opened an outlet positive power supply are met, a protection action logic signal is output; the outlet execution module (300) receives the protection action logic signal and drives the relay to output a tripping contact to realize fault isolation.
10. The method for phase-to-phase backup protection of a main transformer high-voltage side according to claim 9, wherein the composite voltage blocking criterion supports a selection of a high-voltage side or a low-voltage side back-voltage blocking, and the blocking is opened as long as one side satisfies a back-voltage condition.

Description

Main transformer high-voltage side interphase backup protection device and method Technical Field The invention relates to the technical field of relay protection of power systems, in particular to a main transformer high-voltage side interphase backup protection device and method. Background In a power system, a transformer is used as core equipment, and the safe and stable operation of the transformer directly influences the power supply reliability of the system. The composite voltage blocking overcurrent protection is an important configuration of the phase backup protection of the transformer and is used for reflecting the phase short circuit faults of the transformer and adjacent elements. The traditional protection device has the following defects of insufficient sensitivity, difficulty in adapting to complex operation conditions of a transformer of a large pumped storage power station, weak anti-interference capability, easiness in misoperation caused by abnormal conditions such as PT disconnection and CT saturation, and incapability of adapting to different main wiring modes and operation requirements due to lack of flexible locking logic configuration. In the prior art, part of protection devices adopt a single DSP architecture, the risk of misoperation caused by hardware faults exists, the composite voltage locking criterion is single, the flexible selection of high and low voltage side back voltage is not considered, the PT disconnection processing mechanism is imperfect, and the protection reliability is affected. Therefore, there is a need to design a high-sensitivity, high-reliability, flexible-configuration composite voltage-blocking over-current protection device and method. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a device and a method for protecting the interphase backup of a main transformer high-voltage side, which improve the sensitivity, reliability and configuration flexibility of protection. In order to solve the defects in the prior art, the invention aims to provide a main transformer high-voltage side alternate backup protection device. In order to achieve the purpose, the technical scheme adopted by the invention is that the main transformer high-voltage side interphase backup protection device comprises: and the signal acquisition module is used for acquiring the electric quantity analog signals of the transformer and outputting two paths of homologous digital signals. The data processing module comprises two mutually independent DSP boards, the two DSP boards respectively receive one path of the homologous digital signals, one path of the two DSP boards executes protection logic calculation and outputs protection action logic signals, and the other path of the two DSP boards executes starting condition judgment and outputs power supply open signals. And the outlet execution module is respectively connected with the two DSP boards and executes isolation action only when the protection action logic signal and the power supply open signal are received at the same time. As an optimal scheme of the main transformer high-voltage side interphase backup protection device, the signal acquisition module comprises an analog input unit, a low-pass filtering unit and an A/D conversion unit. The analog input unit is used for collecting an electric analog signal of the transformer, the output end of the analog input unit is connected with two paths of independent analog processing channels, and each path of channel comprises a low-pass filtering unit and an A/D conversion unit which are sequentially connected and is used for filtering high-frequency interference in the signal, converting the high-frequency interference into a digital signal and respectively outputting the digital signal to the two DSP boards. As an optimal scheme of the main transformer high-voltage side interphase backup protection device, the electric quantity analog signal collected by the analog quantity input unit comprises an alternating voltage signal and an alternating current signal. The alternating current signal comprises alternating voltage of a high-voltage side and a low-voltage side of the main transformer, negative sequence voltage and zero sequence voltage, and the alternating current signal comprises backup current of the high-voltage side and backup current of the low-voltage side. The main transformer high-voltage side alternate backup protection device comprises a switching value input module, a data processing module and a protection pressing plate switching module, wherein the switching value input module is used for acquiring an external switching signal, the external switching signal is transmitted to the data processing module after being isolated by light isolation, and the external switching signal comprises a breaker position signal, a PT disconnection signal and a protection pressing plate switching signal. As an optimal scheme of the main t