CN103176083A - Method for diagnosing impact on metallic oxide arrester electrification test from inter-phase interference - Google Patents

Abstract

The invention discloses a method for diagnosing the influence of phase-to-phase interference on the live test of a metal oxide arrester. This method first obtains the instantaneous value of the voltage at each sampling time from the high-voltage side leads of the A-phase and C-phase metal oxide arresters, and uses the Fourier algorithm to calculate the voltage phase angle. Obtain the instantaneous value of the leakage current at each sampling time and separate the resistive current from it, use the Fourier algorithm to calculate the phase angle of the resistive current, calculate the interference coefficient, and diagnose based on the comparison between the interference coefficient and the set value. The method of the present invention realizes the accurate diagnosis of the influence of interphase interference on the electrification test result of the metal oxide arrester. If the electrification test result of the metal oxide arrester is abnormal due to the interphase interference, the diagnosis result of the method of the present invention can be used for the tester to correctly analyze the metal oxidation. It provides a strong reference basis for the insulation performance of physical arresters, and effectively avoids misjudgments caused by abnormal test results caused by phase-to-phase interference.

Description

Interphase interference affects the diagnostic method of situation on the metal oxide arrester live testing

Technical field

The present invention relates to the electric equipment protection field, specifically relating to a kind of interphase interference affects the diagnostic method of situation on the metal oxide arrester live testing.

Background technology

Metal oxide arrester obtains widespread use due to its superior through-flow characteristic as the power equipment overvoltage protective device.In metal oxide arrester live testing process, because B phase metal oxide arrester exerts an influence to A phase, C phase metal oxide arrester leakage current by stray capacitance, make the leakage current of the A that flows through, C phase metal oxide arrester down conductor become large or diminish, namely interphase interference can cause that A phase, C phase metal oxide arrester live testing result are bigger than normal or less than normal.If interphase interference is very little, interphase interference is little on A phase, the impact of C phase metal oxide arrester live testing result, and the tester can directly analyze A phase, C phase metal oxide arrester insulating property according to test result; If interphase interference is very large, interphase interference can cause A phase, C phase metal oxide arrester live testing results abnormity, and the tester judges according to abnormal test result, easily judges by accident, thereby cause unnecessary interruption maintenance, cause the supply load loss.

Summary of the invention

The object of the invention is to overcome the deficiency that prior art exists, providing a kind of and diagnosing accurately, effectively avoid judging by accident disconnected interphase interference affects the diagnostic method of situation on the metal oxide arrester live testing.

The objective of the invention is to realize by following approach:

Interphase interference affects the diagnostic method of situation on the metal oxide arrester live testing, it is characterized in that, comprises the following steps:

(1) calculation processing apparatus that electric quantity collector is provided and is attached thereto, electric quantity collector obtains the instantaneous voltage of each sampling instant from A phase, C phase metal oxide arrester high-side lead respectively, and sending calculation processing apparatus to, calculation processing apparatus utilizes Fourier algorithm to calculate respectively the phase angle theta of A phase, C phase lightning arrester high side voltage _A, θ _C

(2) electric quantity collector obtains respectively the Leakage Current instantaneous value of each sampling instant from A phase, C phase metal oxide arrester down conductor, and sending calculation processing apparatus to, calculation processing apparatus is isolated the current in resistance property of each sampling instant t from the Leakage Current of the A phase metal oxide arrester down conductor of flowing through $i_{\mathrm{rA}}\left(t\right)=i_A\left(t\right)-I_{\mathrm{Am}}\sin \left[\frac{2\mathrm{\π}(t-t_0)}{T_0}\right],$ Calculation processing apparatus is isolated the current in resistance property of each sampling instant t from the Leakage Current of the C phase metal oxide arrester down conductor of flowing through $i_{\mathrm{rC}}\left(t\right)=i_C\left(t\right)-I_{\mathrm{Cm}}\sin \left[\frac{2\mathrm{\π}(t-t_1)}{T_1}\right];$

Wherein, I _AmBe first maximal value after the Leakage Current waveform zero passage of the A phase metal oxide arrester down conductor of flowing through; I _CmBe first maximal value after the Leakage Current waveform zero passage of the C phase metal oxide arrester down conductor of flowing through; T is sampling instant; T ₀Constant cycle length for the Leakage Current of the A phase metal oxide arrester down conductor of flowing through; T ₁Constant cycle length for the Leakage Current of the C phase metal oxide arrester down conductor of flowing through; i _A(t) be the flow through Leakage Current instantaneous value of A phase metal oxide arrester down conductor of t sampling instant; i _C(t) be the flow through Leakage Current instantaneous value of C phase metal oxide arrester down conductor of t sampling instant;

(3) calculation processing apparatus utilizes Fourier algorithm to calculate respectively its phase angle α to the A phase that calculates in step (2), the current in resistance property in C phase arrester ground downlead Leakage Current _A, α _C, calculation processing apparatus further calculates interference coefficient $\mathrm{\β}=\frac{({\mathrm{\α}}_C-{\mathrm{\θ}}_C)-({\mathrm{\α}}_A-{\mathrm{\θ}}_A)}{2};$

(4) setting valve β is set _set, interphase interference is differentiated by following criterion by calculation processing apparatus the situation that affects of metal oxide arrester live testing: judgement β〉and β _setWhether set up, if β β _setSet up, be judged as interphase interference very large on the impact of metal oxide arrester live testing result; If β＜β _setSet up, be judged as interphase interference and can not impact metal oxide arrester live testing result; Calculation processing apparatus output diagnostic result also sends alarm signal.

Technique scheme has following beneficial effect:

the inventive method can realize that interphase interference affects the Precise Diagnosis of situation on metal oxide arrester live testing result, if when causing metal oxide arrester live testing results abnormity due to interphase interference, application the inventive method diagnostic result can be tester's Correct Analysis metal oxide arrester insulating property provides strong reference frame, avoid effectively that to cause test result extremely to cause that the tester judges by accident disconnected because of interphase interference, thereby reduce the metal oxide arrester interruption maintenance time, reduce loss of outage, ensure power grid security, economical, stable operation.

Description of drawings

Fig. 1 uses a kind of interphase interference of the present invention the metal oxide arrester live testing to be affected the process flow diagram of the diagnostic method of situation.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, embodiment of the present invention is done further and described in detail.

Fig. 1 uses a kind of interphase interference of the present invention the metal oxide arrester live testing to be affected the process flow diagram of the diagnostic method of situation.The calculation processing apparatus that the embodiment of the present invention provides a kind of electric quantity collector and is attached thereto, electric quantity collector obtains the instantaneous voltage of each sampling instant from A phase, C phase metal oxide arrester high-side lead respectively, and sending calculation processing apparatus to, calculation processing apparatus utilizes Fourier algorithm to calculate respectively the phase angle theta of A phase, C phase lightning arrester high side voltage _A, θ _C

Electric quantity collector obtains respectively the Leakage Current instantaneous value of each sampling instant from A phase, C phase metal oxide arrester down conductor, and sending calculation processing apparatus to, calculation processing apparatus is isolated the current in resistance property of each sampling instant t from the Leakage Current of the A phase metal oxide arrester down conductor of flowing through $i_{\mathrm{rA}}\left(t\right)=i_A\left(t\right)-I_{\mathrm{Am}}\sin \left[\frac{2\mathrm{\π}(t-t_0)}{T_0}\right],$ Calculation processing apparatus is isolated the current in resistance property of each sampling instant t from the Leakage Current of the C phase metal oxide arrester down conductor of flowing through $i_{\mathrm{rC}}\left(t\right)=i_C\left(t\right)-I_{\mathrm{Cm}}\sin \left[\frac{2\mathrm{\π}(t-t_1)}{T_1}\right];$

Wherein, I _AmBe first maximal value after the Leakage Current waveform zero passage of the A phase metal oxide arrester down conductor of flowing through; I _CmBe first maximal value after the Leakage Current waveform zero passage of the C phase metal oxide arrester down conductor of flowing through; T is sampling instant; T ₀Constant cycle length for the Leakage Current of the A phase metal oxide arrester down conductor of flowing through; T ₁Constant cycle length for the Leakage Current of the C phase metal oxide arrester down conductor of flowing through; i _A(t) be the flow through Leakage Current instantaneous value of A phase metal oxide arrester down conductor of t sampling instant; i _C(t) be the flow through Leakage Current instantaneous value of C phase metal oxide arrester down conductor of t sampling instant;

Calculation processing apparatus utilizes Fourier algorithm to calculate respectively its phase angle α to the current in resistance property in A phase, C phase arrester ground downlead Leakage Current _A, α _C, calculation processing apparatus further calculates interference coefficient

Setting valve β is set _set, interphase interference is differentiated by following criterion by calculation processing apparatus the situation that affects of metal oxide arrester live testing: judgement β〉and β _setWhether set up, if β β _setSet up, be judged as interphase interference very large on the impact of metal oxide arrester live testing result; If β＜β _setSet up, be judged as interphase interference and can not impact metal oxide arrester live testing result; Calculation processing apparatus output diagnostic result also sends alarm signal.

When causing metal oxide arrester live testing results abnormity due to interphase interference, according to existing metal oxide arrester live testing technology, the tester can't judge because the metal oxide arrester insulating property have problem and cause that test result is abnormal, or because interphase interference causes metal oxide arrester live testing results abnormity.The diagnostic result of using the inventive method can be tester's Correct Analysis metal oxide arrester insulating property provides strong reference frame, thereby avoid effectively that to cause test result extremely to cause that the tester judges by accident disconnected because of interphase interference, and then be conducive to reduce the metal oxide arrester interruption maintenance time, reduce loss of outage, ensure power grid security, economy, stable operation.

The above is only preferred embodiment of the present invention; but protection scope of the present invention is not limited to this; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses, the variation that can expect easily or replacement are within all should being encompassed in protection scope of the present invention.

Claims (1)

1. phase-to-phase interference is characterized in that, comprises the following steps: (1) Provide a power collection device and a calculation processing device connected to it. The power collection device obtains the instantaneous voltage value at each sampling time from the lead wires of the high voltage side of the A-phase and C-phase metal oxide arrester respectively, and transmits it to the calculation processing device to calculate The processing device uses the Fourier algorithm to calculate the phase angles θ _A and θ _C of the high-voltage side voltages of the A-phase and C-phase arresters respectively; (2) The power acquisition device obtains the instantaneous value of the leakage current at each sampling time from the grounding down conductor of the metal oxide arrester of phase A and phase C respectively, and transmits it to the calculation processing device, and the calculation processing device flows through the metal oxide surge arrester of phase A The resistive current at each sampling time t is separated from the leakage current of the grounding down conductor of the arrester $i_{\mathrm{rA}}\left(t\right)=i_A\left(t\right)-I_{\mathrm{Am}}\sin \left[\frac{2\mathrm{\&pi;}(t-t_0)}{T_0}\right],$ The calculation and processing device separates the resistive current at each sampling time t from the leakage current flowing through the grounding down conductor of the C-phase metal oxide arrester $i_{\mathrm{rC}}\left(t\right)=i_C\left(t\right)-I_{\mathrm{cm}}\sin \left[\frac{2\mathrm{\&pi;}(t-t_1)}{T_1}\right];$ Among them, I _Am is the first maximum value of the leakage current waveform flowing through the grounding down conductor of the metal oxide arrester of phase A after zero crossing; I _Cm is the leakage current waveform flowing through the grounding down conductor of the metal oxide arrester of phase C The first maximum value after zero crossing; t is the sampling time; T ₀ is the periodic time constant of the leakage current flowing through the grounding down conductor of the metal oxide arrester of phase A; T ₁ is the time constant of the leakage current flowing through the grounding of the metal oxide arrester of phase C The periodic time constant of the leakage current of the down conductor; i _A (t) is the instantaneous value of the leakage current flowing through the grounding down conductor of the metal oxide arrester of phase A at the sampling time t; i _C (t) is the instantaneous value of the leakage current flowing through the C The instantaneous value of the leakage current of the grounding down conductor of the phase metal oxide arrester; (3) The calculation and processing device uses the Fourier algorithm to calculate the phase angles α A and _α C of the resistive current in the leakage current of the A-phase and _C -phase arrester grounding down conductors calculated in step (2), and calculates and processes The device further calculates the interference coefficient $\mathrm{\&beta;}=\frac{({\mathrm{\&alpha;}}_C-{\mathrm{\&theta;}}_C)-({\mathrm{\&alpha;}}_A-{\mathrm{\&theta;}}_A)}{2};$ (4) Set the setting value β _set , and the influence of phase-to-phase interference on the live test of the metal oxide arrester is judged by the calculation and processing device through the following criteria: judge whether β>β _set is established, and if β>β _set is established, it is judged as Interphase interference has a great influence on the live test results of metal oxide arresters; if β<β _set holds, it is judged that interphase interference will not affect the live test results of metal oxide arresters; the calculation and processing device outputs diagnostic results and sends out alarm signals.