CN-119471237-B - Generator stator corona degradation monitoring method and system based on partial discharge

CN119471237BCN 119471237 BCN119471237 BCN 119471237BCN-119471237-B

Abstract

The application provides a method and a system for monitoring corona degradation of a generator stator based on partial discharge, wherein the method comprises the steps of obtaining a multi-fault superposition global PRPD (partial discharge pulse pattern) of the generator stator at each moment in a preset time period, marking a plurality of corona discharge partial pattern areas in the multi-fault superposition global PRPD, obtaining the discharge quantity of each pulse amplitude and each pulse phase in positive polarity partial discharge pulse and each pulse phase of the generator stator at each moment in the preset time period, the discharge quantity of each pulse amplitude and each pulse phase of negative polarity partial discharge pulse, determining the discharge pulse duty ratio, the discharge pulse quantity and the discharge pulse amplitude in each corona discharge partial pattern area at each moment in the preset time period, and determining whether the corona performance of the generator stator is degraded or not according to the discharge pulse duty ratio, the discharge pulse quantity and the discharge pulse amplitude. According to the technical scheme provided by the application, the corona state of the insulation partial discharge of the original generator can be accurately and effectively monitored.

Inventors

YANG ZENGJIE
CAO JUNSHUAI
LV AIJUN
LI RUIPENG
LIU ZHONGREN
ZHANG XUEMING
WU YONGZHI
SUN YONGXIN
ZHAO XIANFENG
GAO JING
XIONG GUOXI
TAN SHANGREN
ZENG LINGLONG

Assignees

华能澜沧江水电股份有限公司
哈动国家水力发电设备工程技术研究中心有限公司

Dates

Publication Date: 20260505
Application Date: 20241104

Claims (6)

1. A method for monitoring corona degradation of a generator stator based on partial discharge, the method comprising: Acquiring a multi-fault superimposed global PRPD (partial pressure pulse generator) map of a generator stator at each moment in a preset period, and marking a plurality of corona discharge local map areas in the multi-fault superimposed global PRPD map; acquiring the discharge quantity of each pulse amplitude and each pulse phase in positive partial discharge pulse and the discharge quantity of each pulse amplitude and each pulse phase in negative partial discharge pulse of the generator stator at each time in a preset period based on a multi-fault superposition global PRPD map of the generator stator at each time in the preset period; Constructing a three-dimensional array at each moment in the preset time period according to the discharge quantity of each pulse amplitude and each pulse phase in the positive partial discharge pulse at each moment in the preset time period and the discharge quantity of each pulse amplitude and each pulse phase of the negative partial discharge pulse; Determining the abscissa and the ordinate of the lower left corner and the abscissa and the ordinate of the upper right corner of each corona discharge local spectrum region at each moment in the preset period based on the three-dimensional array at each moment in the preset period; Dividing the abscissa of the lower left corner by a preset granularity to obtain the abscissa of the first coordinate of the lower left corner, and obtaining the ordinate of the lower left corner to obtain the ordinate of the first coordinate of the lower left corner; dividing the abscissa of the upper right corner by a preset granularity as the abscissa of the first coordinate of the upper right corner, and taking the ordinate of the upper right corner as the ordinate of the first coordinate of the upper right corner; Acquiring the discharge quantity in each corona discharge local map region at each time in the preset time period; determining the duty ratio and the number of discharge pulses in the corona discharge local spectrum region according to the number of discharge in the corona discharge local spectrum region, the first coordinate of the left lower corner and the first coordinate of the right upper corner of the corona discharge local spectrum region; determining a discharge pulse amplitude in the corona discharge local spectrum region according to a first coordinate of a lower left corner and a first coordinate of an upper right corner of the corona discharge local spectrum region; Determining whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local map region at each time in the preset period; Wherein, the calculation formula of the discharge pulse duty ratio in the corona discharge local spectrum area is as follows: K s =H/((x2-x1+1) (y2-y1+1)) Wherein K s is a duty cycle of a discharge pulse in the s-th corona discharge partial map region, H is a discharge quantity in the s-th corona discharge partial map region, x1 is an abscissa of a first coordinate of a lower left corner, y1 is an ordinate of a first coordinate of a lower left corner, x2 is an abscissa of a first coordinate of an upper right corner, and y2 is an ordinate of a first coordinate of an upper right corner; the calculation formula of the discharge pulse quantity in the corona discharge local spectrum area is as follows: In the formula, For the number of discharge pulses in the region of the s-th corona discharge partial pattern, , For z, the discharge number; the calculation formula of the discharge pulse amplitude in the corona discharge local spectrum area is as follows: wherein QM s is the discharge pulse amplitude in the s-th corona discharge partial spectrum region, R is the upper limit value of the measuring range, and F is the number of panes of the amplitude.
2. The method of claim 1, wherein marking a plurality of corona discharge local spectrum regions in the multi-fault superimposed global PRPD spectrum comprises: Acquiring each phase angle range when the generator stator discharges; And marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum at each moment in the preset period based on the phase angle ranges.
3. The method of claim 2, wherein the constructing a three-dimensional array of each time instant in the preset time period according to the discharge quantity under each pulse amplitude and each pulse phase in the positive partial discharge pulse and each pulse amplitude and each pulse phase in the preset time period, and the discharge quantity under each pulse amplitude and each pulse phase in the negative partial discharge pulse comprises: Sequentially numbering each pulse amplitude of the negative-polarity partial discharge pulse at the ith moment to each pulse amplitude in the positive-polarity partial discharge pulse from zero, and taking each pulse amplitude number as a y coordinate; Respectively numbering each pulse phase in the positive partial discharge pulse and each pulse phase in the negative partial discharge pulse at the ith moment from zero in sequence, and taking each pulse phase as an x coordinate; taking the discharge quantity of each pulse amplitude and each pulse phase in the positive partial discharge pulse at the ith moment and the discharge quantity of each pulse amplitude and each pulse phase of the negative partial discharge pulse as the z coordinate of the corresponding pulse amplitude and the corresponding pulse phase; constructing a three-dimensional array of the ith moment based on the y coordinate, the x coordinate and the z coordinate of the ith moment; wherein I belongs to I, which is the total number of times in a preset period.
4. The method of claim 3, wherein said determining whether corona performance of said generator stator is degraded based on a discharge pulse duty cycle, a number of discharge pulses, and a discharge pulse amplitude in each corona discharge local map region at each time instant within said predetermined period comprises: Constructing a continuous sample characteristic series of the preset time period according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local map region at each time in the preset time period; And drawing a trend curve based on the continuous sample characteristic series of the preset period, and judging whether the corona performance of the generator stator is deteriorated or not based on the trend curve.
5. A partial discharge based generator stator corona degradation monitoring system, the system comprising: The first acquisition module is used for acquiring a multi-fault superimposed global PRPD (partial pressure pulse generator) spectrum of the generator stator at each moment in a preset period of time and marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum; The second acquisition module is used for acquiring the discharge quantity of each pulse amplitude and each pulse phase in the positive partial discharge pulse and the discharge quantity of each pulse amplitude and each pulse phase in the negative partial discharge pulse of the generator stator at each time in the preset time period based on the multi-fault superposition global PRPD map of each time of the generator stator in the preset time period; the first determining module is used for constructing a three-dimensional array at each moment in the preset time period according to the discharge quantity of each pulse amplitude and each pulse phase in the positive partial discharge pulse at each moment in the preset time period and the discharge quantity of each pulse amplitude and each pulse phase of the negative partial discharge pulse; The first determining module is further used for determining the abscissa and the ordinate of the lower left corner and the abscissa and the ordinate of the upper right corner of each corona discharge local spectrum region at each moment in the preset period based on the three-dimensional array at each moment in the preset period; The first determining module is further configured to divide an abscissa of the lower left corner by a preset granularity as an abscissa of the first coordinate of the lower left corner, and an ordinate of the lower left corner as an ordinate of the first coordinate of the lower left corner; the first determining module is further configured to divide an abscissa of the upper right corner by a preset granularity as an abscissa of the first coordinate of the upper right corner, and an ordinate of the upper right corner as an ordinate of the first coordinate of the upper right corner; the first determining module is also used for obtaining the discharge quantity in each corona discharge local map region at each moment in the preset period; The first determining module is further used for determining the duty ratio and the number of the discharge pulses in the corona discharge local spectrum region according to the number of the discharge in the corona discharge local spectrum region, the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region; The first determining module is further used for determining the discharge pulse amplitude in the corona discharge local spectrum region according to the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region; The second determining module is used for determining whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge partial map region at each moment in the preset period; Wherein, the calculation formula of the discharge pulse duty ratio in the corona discharge local spectrum area is as follows: K s =H/((x2-x1+1) (y2-y1+1)) Wherein K s is a duty cycle of a discharge pulse in the s-th corona discharge partial map region, H is a discharge quantity in the s-th corona discharge partial map region, x1 is an abscissa of a first coordinate of a lower left corner, y1 is an ordinate of a first coordinate of a lower left corner, x2 is an abscissa of a first coordinate of an upper right corner, and y2 is an ordinate of a first coordinate of an upper right corner; the calculation formula of the discharge pulse quantity in the corona discharge local spectrum area is as follows: In the formula, For the number of discharge pulses in the region of the s-th corona discharge partial pattern, , For z, the discharge number; the calculation formula of the discharge pulse amplitude in the corona discharge local spectrum area is as follows: wherein QM s is the discharge pulse amplitude in the s-th corona discharge partial spectrum region, R is the upper limit value of the measuring range, and F is the number of panes of the amplitude.
6. A computer readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the method according to any of claims 1-4.

Description

Generator stator corona degradation monitoring method and system based on partial discharge Technical Field The application relates to the technical field of monitoring of insulation states of generators in intelligent power plants, in particular to a method and a system for monitoring corona degradation of a generator stator based on partial discharge. Background The large-scale generator is a core component for power generation of a power plant, and is characterized in that shutdown events caused by stator insulation faults are counted to be more than 40% according to literature, an insulation partial discharge monitoring system is arranged on a generator stator winding to prevent an unplanned shutdown event from happening in advance in an insulation state, the insulation state is judged by continuously detecting partial discharge amplitude characteristic change, planned maintenance and overhaul are carried out according to the insulation state, and the insulation performance is recovered. However, in engineering application, the stator insulation of the large-scale generator is a distributed system, multiple faults with different risks in the system are overlapped, the mode diagram is an overall global mode aiming at the overall partial discharge detection of the phase winding, the discharge amplitude of the mode diagram is only representative of the discharge fault with the largest discharge capacity, the mode diagram is possibly external interference, the metal tip discharge is not fault discharge with high risk to the insulation system, and the insulation internal discharge, corona discharge and slot discharge with high risk are always reflected only in the local part of the mode diagram and have smaller amplitude due to propagation attenuation and the like, so that the comprehensive amplitude characteristic of the existing monitoring system aiming at the insulation partial discharge can not effectively monitor the insulation degradation development, even the insulation fault is stopped, the monitoring system is not abnormally reflected, and the failure condition is monitored on line. The problem of stator corona of large-scale air-cooled generator, the deterioration of insulation and corona prevention performance is a relatively convex stator insulation problem in large-scale hydraulic generator in recent years, and it is necessary to research the partial discharge characteristic of the corona problem and develop continuous monitoring in a targeted manner. Disclosure of Invention The application provides a generator stator corona degradation monitoring method and system based on partial discharge, which at least solve the technical problem that the prior art cannot effectively monitor the development of insulation corona degradation. An embodiment of a first aspect of the present application proposes a method for monitoring corona degradation of a stator of a generator based on partial discharge, the method comprising: Acquiring a multi-fault superimposed global PRPD (partial pressure pulse generator) map of a generator stator at each moment in a preset period, and marking a plurality of corona discharge local map areas in the multi-fault superimposed global PRPD map; acquiring the discharge quantity of each pulse amplitude and each pulse phase in positive partial discharge pulse and the discharge quantity of each pulse amplitude and each pulse phase in negative partial discharge pulse of the generator stator at each time in a preset period based on a multi-fault superposition global PRPD map of the generator stator at each time in the preset period; Determining the duty ratio, the number and the amplitude of the discharge pulse in each corona discharge local map region at each time in the preset time period according to the pulse amplitude and the discharge quantity under each pulse phase in each positive partial discharge pulse and the pulse amplitude and the discharge quantity under each pulse phase in each negative partial discharge pulse; and determining whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum region at each time in the preset period. Preferably, the marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum includes: Acquiring each phase angle range when the generator stator discharges; And marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum at each moment in the preset period based on the phase angle ranges. Further, the determining the duty ratio, the number of discharge pulses and the amplitude of discharge pulses in each corona discharge local map region at each time in the preset period according to the amplitude of each pulse in the positive partial discharge pulse and the number of discharge in