JPS5850476A - Testing method for superposition of harmonic conponent - Google Patents

Abstract

PURPOSE:To superpose a fundamental wave and a desired harmonic component synchronously by forming a parallel resonance circuit by connecting an impedance element showing a reactance acting reversely to an element to be tested, and by circulating a harmonic current generated by a harmonic component generating element. CONSTITUTION:When the rated voltage of an element 2 to be tested is applied from a fundamental-wave power source 1, harmonic components f3, f5, f7... are generated from a harmonic component generating element 3. The current I5 of the fifth harmonic component f5 out of them is enlarged in resonance by a parallel resonance circuit of the fifth harmonic component formed of the element 2 to be tested and of an impedance element 4, and is made to circulate through this parallel resonance circuit. A superposed current of a fundamental wave f0 and the fifth harmonic component flows through the element 2 to be tested, and thereby a desired test on noise or rise in temperature is conducted. Since the fundamental wave and the desired harmonic current can be superposed in the element to be tested, by means of one power source, in this way, the two currents can be synchronized, and thus the reliability of a test of superposition can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a harmonic superposition test method for electrical devices connected to an electric power or distribution system, such as a phase advancing capacitor, a series reactor, or a filter device constituting an AC filter.

As is well known, in this type of electrical equipment, in addition to the 50 Hz or 60 Hz fundamental current of the power system to which it is connected, a large amount of harmonic power flows into the electrical equipment.

Therefore, when conducting noise or temperature rise tests on electrical equipment connected to power systems containing such harmonic currents, it is desirable to conduct them under the conditions described above.

From this point of view, in order to simply superimpose both components, it is recommended to connect a fundamental wave power source and a harmonic power source in series to the sample under test, and measure noise by simultaneously supplying power from both power sources. However, with this method, other power frequency components will flow into both power supplies, and if a generator is used as a power source, overvoltage will be present in the excitation winding, and if a commercial power source is used, In some cases, there is a disadvantage that harmonic current flows to the commercial power supply side.

In view of the above-mentioned matters, the present invention connects an impedance element that exhibits an opposite actance to the sample under test at a harmonic frequency superimposed in parallel to the sample under test to form a parallel resonant circuit. This is designed to circulate the harmonic current generated by the harmonic generating element.

An embodiment of the present invention will be explained below based on the drawings. In addition, in the following description, for convenience, the case where the fifth harmonic current is superimposed on the fundamental wave current will be explained in detail. In the figure, 1 is a fundamental wave power source, and 2 is an electrical device under test connected to the fundamental wave power source 1. In the illustrated example, it is composed of a capacitor C1, a series reactor L, a discharge coil ylzDc, and a switch S. This is a reactive power adjustment device that generates reactive power.

The sample 2 exhibits capacitive actance for the fundamental wave fO of the fundamental wave power supply 1, and exhibits inductive actance for the superimposed fifth harmonic fs. Reference numeral 6 denotes a harmonic generation element connected in parallel (or in series) to the sample 2, which is made up of, for example, a coil wound around an iron core. By applying electricity to the saturation magnetic flux density region where the magnetic flux is saturated, as shown in Figure 6, the third wave outside the fundamental wave fO is
Harmonic current I5, such as harmonic f3, fifth harmonic f5, and seventh harmonic f7. I5, 7 are generated, and these harmonic currents 5, I5, and F are energized to the sample 2 in a manner superimposed on the fundamental wave current. As the harmonic generating element 2, a transformer in a supersaturated state with the secondary side open or a saturated reactor can be used. Reference numeral 4 denotes an impedance element that exhibits an actance opposite to that of the sample 2 with respect to the fifth harmonic f5 superimposed on the sample 2, and is a resonant capacitor in the illustrated example. This impedance element 4 is connected in parallel to the specimen 2 to form a parallel resonant circuit that resonates in parallel at the superimposed fifth harmonic f5. 5 is a compensating impedance element provided as necessary, and in the illustrated example, the entire parallel resonant circuit consisting of the specimen 2 and the impedance element 4 has a large phase advance capacity with respect to the fundamental wave fO. This is a compensating reactor connected in parallel with the sample 2 to exhibit the opposite effect. Due to the existence of this compensation reactor 5, the fundamental wave 1! The power capacity of source 1 is reduced. In addition, in determining the capacity of this compensation impedance 5,
Since the purpose is to reduce the power supply capacity, it goes without saying that it should be selected within a range that does not adversely affect the superimposition test.

Therefore, in the circuit configuration described above, when the rated voltage of the specimen 2 is applied from the fundamental wave power supply 1, the harmonics f3, f5, f7, etc. are generated from the harmonic generation element 6, and the The current ■5 of the fifth harmonic f5 is resonated amplified by the parallel resonant circuit of the fifth harmonic consisting of the specimen 2 and the impedance element 4, and circulates through this parallel resonant circuit. A current in which the wave fo and the fifth harmonic are superimposed flows, and a desired noise or temperature rise test is performed. Note that other harmonics f3, f7, . . . generated by the harmonic generation element 3
The harmonic currents 3, F... are small and are not magnified in the circuit configuration described above, so their influence on various tests is extremely small.

The harmonic current can be adjusted as appropriate by providing a tap on the harmonic generation element 6 and adjusting its excitation current, or by adjusting the impedance value of the impedance element 4 to slightly shift its resonance.

5- As detailed above, according to the present invention, it is possible to superimpose the fundamental wave and the desired harmonic current on the specimen using one power supply, and furthermore, since one power supply is used, The training currents can be synchronized, which has the effect of improving the reliability of this type of superposition test.

In addition, although the three-phase circuit was detailed in the above-mentioned embodiment,
If the specimen is a single-phase electrical device, it goes without saying that the present invention can be implemented by configuring a single-phase circuit.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram for explaining one embodiment of the present invention, Figs. 2 and 6 are characteristic diagrams of harmonic generation elements, and Fig. 2 shows the relationship between excitation current and applied voltage. 3 shows the relationship between current and frequency. 1: Fundamental wave power supply, 2: Test sample, 3: Harmonic generation element, 4
: Impedance element, 5: Compensation impedance element. Patent Applicant Nissinden Ihiki Co., Ltd. Representative Director 4 Masakatsu Yamawaki 6- - Whip Mi ρ Fuugada Procedural Amendment (Method) % Formula % 1. Indication of the case 1982 Patent Application No. 150379 2. Invention Name: Harmonic superposition test method 3, relationship with the case of the person making the amendment Patent applicant Postal code: 615 Address: 47, Umezu Takaune-cho, Ukyo-ku, Kyoto City Detailed description of the invention in the specification. 5. Contents of correction

Claims (1)

[Claims] / A harmonic generation element is connected in parallel or in series to a specimen connected to a fundamental wave power source, and a harmonic frequency superimposed on the specimen has an opposite effect to the actance of the specimen. A harmonic superposition test method in which an impedance element exhibiting a positive actance is connected in parallel to the specimen to form a parallel resonant circuit. The harmonic superposition test method according to claim 1, wherein the λ harmonic generation element is provided with an adjustment tap. The harmonic superposition test method according to claim 1, wherein the three impedance elements are provided with adjustment terminals.