CN103076492A - Angular difference correction method based on mutual inductor measured power - Google Patents

Abstract

The invention discloses an angular difference correction method based on mutual inductor measured power. The method comprises the following steps of: respectively measuring phase angle errors caused by a voltage transformer, a current transformer and a circuit through pre-applying multiple groups of different standard signal source signals; and taking phase angle errors of multiple groups of input-referred points as a basis, and correcting signals to be measured according to a multi section linear error correction manner, so that the aim of obtaining an ideal power measurement accuracy angular difference correction method can be realized through software correction without adding any hardware or improving the accuracy class of hardware components.

Description

A kind of angular difference modification method of measuring power based on mutual inductor

Technical field

A kind of angular difference modification method based on mutual inductor measurement power of the present invention relates to a kind of electric parameter measurement technical field, particularly measures the technical field of the angular difference correction of power based on the mutual inductor conversion.

Background technology

Along with modernization; the fast development of automated production; electric energy metrical and relay protection are used and to be promoted and to approve in the electric system; mutual inductor is widely used; the voltage transformer (VT) summation current transformer can produce angular difference when primary side and secondary side conversion; when the angular difference of both generations varies in size; will make the signal of measurement and actual signal produce the angular difference error; have influence on the precision of power measurement; at electric current; when voltage input size changes; the angular difference of mutual inductor also can respective change; in the measuring circuit to electric current; voltage signal carries out filtering and amplifies also can producing angular difference, and these situations all make must Measurement accuracy power and electric energy measurement difficult.

Summary of the invention

The objective of the invention is in order to overcome mutual inductor and the electric current of circuit generation and the deficiency that the voltage angular difference affects measuring accuracy in power measurement, design a kind of any hardware that do not need to increase, do not need to improve the hardware component accuracy class, only just can obtain the method for the angular difference correction of desirable Accuracy of Power Measurement by software correction.

Its technical scheme that adopts is: by applying in advance several groups of different standard signal source signals, the phase angle error that causes of measuring voltage mutual inductor, current transformer and circuit respectively, take several groups of phase angle errors of inputting reference point as the basis, press the linear error correcting system of multistage and proofread and correct measured signal, concrete checking procedure is as follows:

(1) the voltage and current signal that applies known voltage and electric current phase angle difference θ 1 accesses device to be verified;

(2) device to be verified calculates the phase angle difference θ 2 of voltage and current;

(3) by known input phase angle difference θ 1 and the phase angle difference θ 2 that measures, phase angle error Δ θ=θ 1-θ 2 be can calculate, θ 2 and Δ θ preserved;

(4) repeat (1) and can obtain the error information of multiple spot to the step of (3), can mark off the multistage zone according to different θ 2;

Concrete measuring process is as follows:

(5) read θ 2 and the Δ θ data of preservation;

(6) calculate measured power P and phase angle difference θ;

(7) find 2 sections of corresponding θ and error delta θ according to measured θ, according to θ 2 and Δ θ linear revise θ, obtain revised θ _Repair, according to θ _RepairObtain P _Repair, finish correction.

The positive effect of implementing after this technology is: at the hardware that does not increase device with do not improve the precision of device hardware component, only by software correction voltage mutual inductor summation current transformer phase angle difference, reach the purpose of the precision that increases substantially power measurement.

Description of drawings

Accompanying drawing 1 is correcting process figure of the present invention;

Accompanying drawing 2 is measurement procedure figure of the present invention;

Embodiment

The invention will be further described below in conjunction with accompanying drawing:

It is as follows to be verified as the concrete checking procedure of example with 15 ° of phase angle differences and 60 ° two 3 sections:

(1) applying the voltage and current phase angle difference is that 15 ° voltage and current signal accesses device to be verified;

(2) device to be verified calculates the phase angle difference of voltage and current, is assumed to be 14 °;

(3) by 14 ° of 15 ° of known input phase angle differences and the phase angle differences measured, can calculate this section phase angle error is 15 °-14 °=1 °, preserves 1 ° of 14 ° of first check points and this phase angle error;

(4) repeat (1) and can obtain the error information of second point to the step of (3), be assumed to be and apply 60 ° in phase angle, measure 57 ° in phase angle, the error phase angle is 3 °, preserves 57 ° of second check points and 3 ° of this phase angle errors;

Can be divided into three sections zones to phase angle according to 14 ° of two check points and 57 °, be respectively one section 0 ° to 14 °, two sections 14 ° to 60 °, three sections 60 ° to 90 °.

This example is only considered the phase angle correction of first quartile, and method of the present invention also goes for complete four-quadrant phase angle and proofreaies and correct as long as enlarge the correction angle.

Concrete measuring process is as follows:

(5) read 1 ° of 14 ° of the first point calibration points of preservation and this phase angle error, 60 ° of second point check points and 3 ° of data of phase angle error;

(6) calculate measured power P and phase angle difference θ, be assumed to be 20.0kW and 45 °;

(7) find 2 sections of corresponding θ and error delta θ according to measured θ, according to θ 2 and Δ θ linear revise θ, obtain revised θ _Repair, according to θ _RepairObtain P _Repair, finish correction.

45 ° in tested phase angle belongs to second segment 14 ° to 57 ° intervals, then θ _L=14 °, θ _H=57 °, Δ θ _L=1 °, Δ θ _H=3 °, θ _Repair=θ+Δ θ _L+ θ (Δ θ _H-Δ θ _L)/(θ _H-θ _L48.09 ° of)=45 °+1 °+45 ° * (3 °-1 °)/(57 °-14 °) ≈, P _Repair=PCOS θ _Repair/ COS θ=20.0kW * COS48.09 °/COS45 ° ≈ 18.89kW.

By above-mentioned steps, can not increase hardware and not improve the hardware component accuracy requirement, only by software correction voltage mutual inductor summation current transformer phase angle difference, reach the purpose of the precision that increases substantially power measurement.

The present invention can count in accuracy class adjustment correction as required, the voltage transformer (VT) summation current transformer of the normal operation linearity 0.1% error, 12 ADC samplings, do not revise and to accomplish that precision is 2 grades power meter as last, adopt 1 point calibration to accomplish 1 grade of power meter to precision, adopt 2 point calibrations can accomplish that precision is 0.5 grade power meter, if need more high precision, need to increase to proofread and correct and count.

Claims (1)

1. measure the angular difference modification method of power based on mutual inductor for one kind, it is characterized in that:

Concrete checking procedure is as follows:

(1) the voltage and current signal that applies known voltage and electric current phase angle difference θ 1 accesses device to be verified;

(2) device to be verified calculates the phase angle difference θ 2 of voltage and current;

(3) by known input phase angle difference θ 1 and the phase angle difference θ 2 that measures, phase angle error Δ θ=θ 1-θ 2 be can calculate, θ 2 and Δ θ preserved;

(4) repeat (1) and can obtain the error information of multiple spot to the step of (3), can mark off the multistage zone according to different θ 2;

Concrete measuring process is as follows:

(5) read θ 2 and the Δ θ data of preservation;

(6) calculate measured power P and phase angle difference θ;

(7) find 2 sections of corresponding θ and error delta θ according to measured θ, according to θ 2 and Δ θ linear revise θ, obtain revised θ _Repair, according to θ _RepairObtain P _Repair, finish correction.

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