CN103048637A - Method for testing broadband characteristic of CVT (capacitor voltage transformer) by high voltage harmonic - Google Patents

Abstract

The invention discloses a method for testing the broadband characteristic of a CVT (capacitor voltage transformer) by a high voltage harmonic in the technical field of electric power. The method has the technical scheme that a high voltage harmonic source of U1 (j omega) is applied between a high voltage end of the CVT and the ground, and the voltage U2 (j omega) of each frequency point at a secondary side and the input voltage U1 (j omega) at a primary side are tested to obtain the broadband transmission characteristic of the CVT through computation. The method disclosed by the invention has the beneficial effects that components of a higher harmonic can be accurately obtained, harmonic interference can be effectively inhibited through harmonic treatment guiding measures, and the quality of electric energy is improved.

Description

The high pressure Harmonic Test Method of CVT broadband properties

Technical field

The invention belongs to the power technology field, relate in particular to a kind of high pressure Harmonic Test Method of CVT broadband properties.

Background technology

Power supply quality is the common focus of paying close attention to of user and electric power enterprise.Along with the development of electrical network, the construction of DC engineering and new forms of energy project, Switching Power Supply, thyristor device, wind-powered electricity generation unit etc. more and more are applied in electrical network.These equipment have improved the utilization ratio of people to electric energy on the one hand, have formed on the other hand a large amount of harmonic currents in electrical network.Its consequence is that other electronic products of same electrical network are interfered, and harmonic current also can cause the overload of electrical network current in middle wire, affects electrical network to the transmittability of electric power.In addition, can cause at electrical network also to the phase control of AC power the variation of current effective value to cause voltage effective value obviously to fluctuate that this voltage fluctuation might cause the flicker of lighting device.Therefore be the requisite test link of electric system to the monitoring of system harmonics.

At present, the method that adopts when carrying out the voltage harmonic test all is harmonic analysis instrument to be directly connected to capacitance type potential transformer CVT secondary side test.The method that this direct application harmonic analysis instrument is carried out test can accurately obtain the capacitance type potential transformer CVT secondary side harmonic components that connects, but all take test 50Hz fundamental voltage electric current as purpose, its bandwidth is narrower when design for the mutual inductors such as capacitance type potential transformer CVT.The correlative study of abroad carrying out shows that the no-load voltage ratio of capacitance type potential transformer CVT is widely different under the different frequency, has the composition that the method for testing of directly utilizing harmonic analysis instrument can not accurately reflect higher hamonic wave now.This solution of problem, depend on the accurate grasp to the broadband properties of mutual inductor harmonic wave frequency range, therefore need to consider in the basis further investigation of grasping capacitance type potential transformer CVT harmonic wave band transmissions harmonic measuring method and the proving installation of capacitance type potential transformer CVT broadband properties.

The measuring method of capacitance type potential transformer CVT mutual inductor broadband properties had some researchs at home and abroad.The scattering parameter method of testing of Excavation Cluster Based on Network Analysis instrument can not reflect the transport property of mutual inductor harmonic wave frequency range under the high-pressure situations; Based on the impulse function mensuration of surge generator, overtension may cause the hidden danger of capacitance type potential transformer CVT loss.The related scientific research units such as University of Toronto are based on testing under capacitance type potential transformer CVT internal magnetic element rated voltage, and operation is difficulty relatively; The low pressure terminal test method of the R﹠D institutions such as the agro-industrial university in American Electric Power research institute and Texas may be damaged capacitance type potential transformer CVT inner member.In a word, the method that does not also have at present a kind of accurately testing capacitor formula voltage transformer (VT) CVT broadband properties both at home and abroad.

Summary of the invention

For the measurement problem of mentioning capacitance type potential transformer CVT broadband properties in the background technology, the present invention proposes a kind of high pressure Harmonic Test Method of CVT broadband properties.

A kind of high pressure Harmonic Test Method of CVT broadband properties is characterized in that, described method specifically may further comprise the steps:

Step 1: utilize the high pressure harmonic source that capacitance type potential transformer is applied harmonic voltage;

Step 2: each frequency input voltage U of testing capacitor formula voltage transformer (VT) primary side ₁The output voltage U of (j ω) and each frequency of secondary side ₂(j ω); Wherein, j is imaginary unit; ω is the phasing degree;

Step 3: according to the output voltage U of each frequency of secondary side that records ₂Each frequency input voltage U of (j ω) and primary side ₁(j ω) calculates the broadband properties H (j ω) of CVT.

In the described step 3, the computing formula of broadband properties is:

$H\left(\mathrm{j\ω}\right)=\frac{U_2\left(\mathrm{j\ω}\right)}{U_1\left(\mathrm{j\ω}\right)}$

Wherein, U ₁(j ω) is each frequency input voltage of primary side; U ₂(j ω) is the output voltage of each frequency; J is imaginary unit; ω is the phasing degree.

The invention has the beneficial effects as follows, can accurately obtain the composition of higher hamonic wave, can effectively suppress humorous wave interference by instructing harness of harmonic wave, improve the quality of power supply.

Description of drawings

Fig. 1 is the internal circuit diagram of high pressure Harmonic Test Method;

Fig. 2 is the external wiring diagram of high pressure Harmonic Test Method;

Fig. 3 is that test macro is once surveyed injecting voltage signal graph and relative harmonic content figure; Wherein, (a) be that test macro is once surveyed the injecting voltage signal graph; (b) be relative harmonic content figure;

Fig. 4 is voltage signal figure and the relative harmonic content figure that the test macro secondary side records; Wherein, (a) be the voltage signal figure that the test macro secondary side records; (b) be relative harmonic content figure;

Fig. 5 is that 220kV capacitance type potential transformer CVT is to broadband properties amplitude frequency diagram and the phase frequency figure of each harmonic; Wherein, (a) be the broadband properties amplitude frequency diagram; (b) be broadband properties phase frequency figure.

Embodiment

Below in conjunction with accompanying drawing, preferred embodiment is elaborated.Should be emphasized that following explanation only is exemplary, rather than in order to limit the scope of the invention and to use.

Each module is pressed appliance wiring figure correct wiring, forms test macro:

Driving source (can be produced the harmonic voltage in 50 times, and wherein 50Hz voltage is the high pressure harmonic source of 1kV to the maximum), (port number is no less than 2 to oscillograph, sampling rate is not less than 10kHz, be used for to gather capacitance type potential transformer CVT primary side and secondary side voltage), computing machine (spectrum analysis software is installed) and capacitance type potential transformer CVT press appliance wiring figure correct wiring, the composition test macro.Such as Fig. 1 and Fig. 2.

(2) utilize the high pressure harmonic source that mutual inductor is applied a series of harmonic wave:

Utilize the high pressure harmonic source that mutual inductor is applied series of harmonic such as Fig. 3.

(3) voltage U of each frequency of test secondary side ₂(j ω):

Each frequency voltage of the secondary side that records as shown in Figure 4.

(4) with the output voltage U of each frequency of secondary side of recording ₂Each frequency input voltage U of (j ω) and primary side ₁(j ω) calculates the broadband properties of capacitance type potential transformer CVT:

Through type (1) can obtain the broadband properties of capacitance type potential transformer CVT, is the ratio of output voltage and input voltage:

$H\left(\mathrm{j\ω}\right)=\frac{U_2\left(\mathrm{j\ω}\right)}{U_1\left(\mathrm{j\ω}\right)}---\left(1\right)$

In the formula, U ₁(j ω) is each frequency input voltage of primary side; The harmonic voltage that applies when being test; U ₂(j ω) each frequency output voltage of secondary side for recording.

This example by computing machine calculate 220kV capacitance type potential transformer CVT to the broadband properties of each harmonic as shown in Figure 5.

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

Claims (2)

1. the high pressure Harmonic Test Method of a CVT broadband properties is characterized in that, described method specifically may further comprise the steps:

Step 1: utilize the high pressure harmonic source that capacitance type potential transformer is applied harmonic voltage;

Step 2: each frequency input voltage U of testing capacitor formula voltage transformer (VT) primary side ₁The output voltage U of (j ω) and each frequency of secondary side ₂(j ω); Wherein, j is imaginary unit; ω is the phasing degree;

Step 3: according to the output voltage U of each frequency of secondary side that records ₂Each frequency input voltage U of (j ω) and primary side ₁(j ω) calculates the broadband properties H (j ω) of CVT.

2. the high pressure Harmonic Test Method of a kind of CVT broadband properties according to claim 1 is characterized in that, in the described step 3, the computing formula of broadband properties is:

$H\left(\mathrm{j\ω}\right)=\frac{U_2\left(\mathrm{j\ω}\right)}{U_1\left(\mathrm{j\ω}\right)}$

Wherein, U ₁(j ω) is each frequency input voltage of primary side; The harmonic voltage that applies when being test; U ₂(j ω) each frequency outgoing side voltage of secondary for recording; J is imaginary unit; ω is the phasing degree.

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