CN102721871A - Method for measuring phase difference of voltage and total current of zinc oxide arrester - Google Patents

Abstract

The invention discloses a method for measuring phase difference of voltage and total current of a zinc oxide arrester. The method comprises the following steps of: measuring a zero crossing point moment of a voltage signal and a zero crossing point moment of a total current signal to obtain a time interval of the zero crossing point moments; sampling in the time interval and calculating to obtain the number of sampling points; and calculating according to a formula to obtain the phase difference of the voltage and the total current of the zinc oxide arrester. According to the method, the difference of the voltage and the total current of the zinc oxide arrester can be conveniently and quickly measured, so that the resistive current can be further obtained.

Description

A kind of method of measuring the voltage and the circuital phase differential of Zinc-Oxide Arrester

Technical field

The present invention relates to the voltage of a kind of measurement Zinc-Oxide Arrester (MOA) and the method for circuital phase differential.

Background technology

Advantages such as Zinc-Oxide Arrester (MOA) is little owing to volume, cost is low, nonlinear characteristic good, through-current capacity is big are widely used in electric system.The accuracy that the MOA current in resistance property is detected is related to whether can judge the work running status that MOA is present accurately, so should manage to improve its measuring accuracy.The total current of MOA and the phase diagram of voltage are as shown in Figure 1.U is the voltage that is added in the MOA two ends among Fig. 1, I _xFor flowing through the total current of MOA, I _cFor flowing through the capacity current of MOA, I _rCurrent in resistance property for our required measurement.If as can be seen from Figure 1 measured total current I _x, so only need measuring voltage to lag behind the phase differential a of electric current, can be by I _r=I _xCosa calculates current in resistance property I _rSo the problem of measuring current in resistance property changes the problem of phase differential between measuring voltage and the electric current into.

Summary of the invention

The object of the present invention is to provide a kind of method that can measure the voltage and the circuital phase differential of Zinc-Oxide Arrester easily and quickly, thereby further obtain current in resistance property, judge the work running status that MOA is present exactly, convenient maintenance it.

The technical scheme that realizes above-mentioned purpose is:

A kind of method of measuring the voltage and the circuital phase differential of Zinc-Oxide Arrester, said voltage is the identical periodic signal of frequency with circuital signal, and the cycle is T, and said method comprises the following steps:

Step 1, the zero crossing that records voltage signal is t constantly ₁Zero crossing moment t with full current signal ₂Thereby, obtain the time interval Δ t between them;

Step 2 is sampled in time interval Δ t, calculates sampling number n, and n is a positive integer, and the sampling period is τ;

Step 3, according to formula:

$\mathrm{\α}=\frac{2\mathrm{\π\Δt}}{T}=\frac{2\mathrm{\π\τn}}{T}$

Obtain the voltage and the circuital phase differential α of Zinc-Oxide Arrester.

The invention has the beneficial effects as follows: the present invention can measure the method for the voltage and the circuital phase differential of Zinc-Oxide Arrester easily and quickly, thereby further obtains current in resistance property, judges the work running status that MOA is present exactly, convenient maintenance to it.

Description of drawings

Fig. 1 is the voltage and the circuital phase diagram of Zinc-Oxide Arrester;

Fig. 2 is the schematic diagram of method of voltage and the circuital phase differential of measurement Zinc-Oxide Arrester of the present invention.

Embodiment

To combine accompanying drawing that the present invention is described further below.

See also Fig. 2, the voltage of measurement Zinc-Oxide Arrester of the present invention and the method for circuital phase differential comprise the following steps:

Step 1 records the zero crossing t constantly of the voltage signal of Zinc-Oxide Arrester ₁Zero crossing moment t with full current signal ₂Thereby, obtain the time interval Δ t between them; Said voltage signal is the identical periodic signal of frequency with full current signal, and the cycle is T;

Step 2 is sampled in time interval Δ t, calculates sampling number n, and n is a positive integer, and the sampling period is τ;

Step 3, according to formula (1):

$\mathrm{\α}=\frac{2\mathrm{\π\Δt}}{T}=\frac{2\mathrm{\π\τn}}{T}---\left(1\right)$

Obtain the voltage and the circuital phase differential α of Zinc-Oxide Arrester, thereby further obtain current in resistance property, judge the work running status that MOA is present exactly.

Above embodiment only supplies to explain the present invention's usefulness; But not limitation of the present invention; The technician in relevant technologies field under the situation that does not break away from the spirit and scope of the present invention, can also make various conversion or modification; Therefore all technical schemes that are equal to also should belong to category of the present invention, should be limited each claim.

Claims (1)

1. method of measuring the voltage and the circuital phase differential of Zinc-Oxide Arrester, said voltage is the identical periodic signal of frequency with circuital signal, and the cycle is T, it is characterized in that, and said method comprises the following steps:

Step 1, the zero crossing that records voltage signal is t constantly ₁Zero crossing moment t with full current signal ₂Thereby, obtain the time interval Δ t between them;

Step 2 is sampled in time interval Δ t, calculates sampling number n, and n is a positive integer, and the sampling period is τ;

Step 3, according to formula:

$\mathrm{\α}=\frac{2\mathrm{\π\Δt}}{T}=\frac{2\mathrm{\π\τn}}{T}$

Obtain the voltage and the circuital phase differential α of Zinc-Oxide Arrester.

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