Small current test abnormality judging method for excitation system
A technology of excitation system and discrimination method, which is applied in the field of measurement, can solve problems that affect the timeliness of abnormal judgment in small current tests, errors in temperature signal measurement, and easy jamming of switches, etc., so as to avoid sudden accidents and control gradual occurrence failures, increased availability, and reduced unnecessary downtime
Active Publication Date: 2018-12-04
CENT CHINA BRANCH OF CHINA DATANG CORP SCI & TECH RES INST CO LTD
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Problems solved by technology
The judgment method is based on indirect quantities, which cannot directly reflect the abnormal nature of the current in the actual operation process.
This includes that the temperature signal measurement is prone to errors, the criterion is not accurate, and the temperature change is a gradual process. Compared with the instantaneous characteristics of the current signal, the measurement period is too long, which can be used as an auxiliary judgment basis, but if it is used as the main criterion. It greatly affects the timeliness of judging the abnormality of the small current test; in addition, the travel switch of the fan is easy to jam, which is greatly interfered by its own physical characteristics, resulting in misjudgment of faults
Method used
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[0027] The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.
[0028] Such as Figure 1-2 As shown, the present invention relates to a method for judging the abnormality of the small current test of the excitation system, comprising the following steps:
[0029] A. Collect the three-phase input current I of the AC side of the rectifier A , I B` , I C and rectifier DC side load current I R ;
[0030] B. Through the formula: I AV =(I A +I B +I C ) / 3, the calculated AC average current I AV ;
[0031] By formula:
[0032]
[0033] Calculate the differential current I D ;
[0034] By formula:
[0035]
[0036] Calculate the DC average current I F ;
[0037] C. When|I F -I R |>0.6I R When the small current test of the excitation system is judged to be abnormal, when the small current test is normal, the DC average current is approximately equal to the DC side load...
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The invention relates to a small current test abnormality judging method for an excitation system. The technical scheme is as follows: A, collecting three-phase input currents IA, IB`, IC of an AC side of a rectifier and load currents IR of a DC side of the rectifier; B, obtaining an AC average current IAV and a differential current ID through calculation; C, if |IF-IR|>0.6IR, judging that small current test abnormality of an excitation system exists; if |IF-1.2IAV|>0.6IR, judging that small current test abnormality of an excitation system exists; if ID>0.6IR, judging that small current test abnormality of an excitation system exists. According to the method, the technical status and deterioration laws of equipment can be known anytime by monitoring current signals of the rectifier of theexcitation system online and calculating the differential current and average current. Moreover, the temperature of bridge arms is monitored, the average temperature of the six bridge arms is calculated and is compared with the maximum temperature and the minimum temperature of the bridge arms, and the data serves as an auxiliary criterion, thereby avoiding sudden accidents, controlling gradual failure and improving the reliability of the system.
Description
technical field [0001] The invention relates to a method for judging abnormality of a small current test of an excitation system, which is used for rapidly diagnosing abnormal faults of the excitation system and preventing expansion of accidents, and belongs to the field of measurement technology. Background technique [0002] The excitation system is one of the important components of the generator excitation system, and its operation reliability is related to the stable operation of the excitation system and the power grid. When the thyristor rectifier bridge fails, it will not only cause the excitation voltage to drop, make the excitation transformer in an asymmetrical or phase-lack operating state, but also cause DC magnetization to overload the other phase thyristors, affecting the safety of the generator excitation system Reliable operation; when the fuse of the power cabinet is blown or the trigger pulse is lost, the output voltage will drop to varying degrees, but du...
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Login to View More IPC IPC(8): G01R31/00G01R19/00
CPCG01R19/0092G01R31/00
Inventor栗占伟黄太昱韩金华贾少华郑豫生李雅琪李姗姗赵伟程
OwnerCENT CHINA BRANCH OF CHINA DATANG CORP SCI & TECH RES INST CO LTD