JPS60125575A - Current measuring device - Google Patents

Abstract

PURPOSE:To make a coaxial shunt or the like small in size by flowing a measuring current to the coaxial shunt only in a required current measuring time. CONSTITUTION:While a large short-circuit current is flowed, a switching breaker 5b for by-pass is closed, and a switching breaker 5a for measurement is opened. At a time several milliseconds before current observation, namely at a point X on a test oscillogram, the breaker 5a is closed, and the breaker 5b is broken simultaneously. Then, a current I2 flowed to a shunt 3 is flowed only before the zero point of the current, and therefore, the energy is reduced. Consequently, measurer of the coaxial shunt or the like is made high-precision and small in size.

Description

[Detailed description of the invention] [Technical field of the invention] ? The present invention relates to a current measuring device used in a breaker test for interrupting a short-circuit incoming current R, such as the one used in Ham IJFIW J.

[Prior art]

Conventionally, there have been devices of this type as shown in FIGS. 1 and 2. In the figure, 1 is a high voltage and large current unit, 2 is a test breaker, 3 is a coaxial shunt, and 4 company bypass circuit breakers.

The operation will be briefly explained. Conventionally, measurements near the current zero point of short-circuit large currents have been carried out using the test circuit shown in FIG. At this time, a large 9L short circuit of several tens of KA to 100 KA flows through the coaxial splitter 3, but the current to be observed is several A before the zero point, and the ratio is 10 times as large. Also, in order to measure a current of several A, the resistance of the coaxial shunt 3 should be made as large as possible to have a good SZN ratio and improve accuracy, but it is necessary to manufacture a coaxial shunt with high resistance that can withstand a current of 100 KA. The thing is.

In terms of energy resistance and electromagnetic force resistance, it is almost impossible. Therefore, measurements are currently being carried out using an improved test circuit as shown in FIG. That is, when the bypass breaker 4Y is closed during the period when the current is flowing through the short circuit, and the bypass breaker 4 is opened several milliseconds before the current zero point, the i! ! All the currents can be measured with a coaxial or C device 3. The oscilloscope at that time is shown in Figure 3. However, with this method, it is impossible to short-circuit with completely zero impedance because 4 bypass circuit breakers are inserted, and therefore, tens of short-circuit large currents are generated in the coaxial shunt 3. There is a drawback that the coaxial flow divider 3 inevitably becomes larger.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above. The purpose is to provide a % flow measuring device that can be miniaturized.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. 1st
In FIGS. 4 and 6, the same parts as in FIGS. 4 and 2 are indicated by the same reference numerals, and 5 is a switch.

5a is a measurement switching breaker which is a component of the switch 5, 5b is a bypass switching breaker which is also a component of the switch 5, and 6 is an operating iron.

T is the upper terminal, and 8 is the lower terminal.

The operation will be briefly explained. In Fig. 4.

During the period when the short circuit large current is flowing, the switching breaker 5b%' for bypass is turned on, and the switching breaker 5a for measurement is kept open. A few milliseconds before the observation, that is, at point X on the test oscillogram shown in Figure 5.

At the same time as the measurement switching breaker Sa& is turned on, the bypass switching breaker 5b is cut off. Then.

Since the current flowing through the coaxial shunt 3 flows only before the current zero point as shown in FIG. 5, its energy can be reduced. Further, in FIG. 6, which is a conceptual diagram of a flow measuring device according to an embodiment of the present invention, by operating the operating rod 6, the - operation turns on the measurement switching breaker 5a and the bypass switching breaker 5b. It is possible to shut off.

Another embodiment of the invention is shown in FIG. 6 a r6b
is operated by a separate operating device (not shown).
With two operations, it is possible to turn on the measurement switching breaker 5a and turn off the binox switching breaker 5b.

〔Effect of the invention〕

As described above, in the current measuring device for measuring f′L&f in a waveform according to the present invention, t of the part to be precisely measured is
Since the configuration is configured such that only m is supplied to the missing measuring device, it is possible to miniaturize the high precision measuring device such as a coaxial shunt.

[Brief explanation of the drawing]

Figure 1 is a short circuit breaker test circuit diagram, Figure 2 is a conventional improved test circuit diagram that eliminates short circuits, and Figure 3 is a waveform diagram in the conventional improved test circuit diagram. ,
FIG. 4 is a test circuit diagram according to an embodiment of the present invention, FIG. 5 is a waveform diagram according to an embodiment of the present invention, and FIG. 6 is a test circuit diagram according to an embodiment of the present invention. Conceptual Diagram 4 of Current Measuring Device FIG. 7 is a conceptual diagram of a current measuring device according to another embodiment of the present invention. Shou...'X Raishodai is the source, 2... Test is the disconnection, 3
...Coaxial shunt, 4...No (breaker for Innox,
5... Switch, 5a... Measurement switching breaker, 5b
...) (Switching breaker for Inokus, 6, 6a, 6b,
...Operation rod. T...upper terminal, 8...lower terminal. In addition, in FIG. 1, the same reference numerals indicate the same or equivalent parts. Patent applicant: Mitsubishi City Machinery Co., Ltd. Figure 1 Figure 4 Figure 5 Figure 6 Procedure amendment group (voluntary) 59.3.23 Showa year, month, day Dear Commissioner of the Japan Patent Office 1, Indication of case Patent application 1986-232664 No. 2, Name of the invention Current measuring device 3, Person making the amendment Representative Hitoshi Katayama Department 5, Subject of the amendment 59.3, 2'3 6, Contents of the amendment The scope of the claims is amended as shown in the attached sheet. 7. A document stating the scope of claims after amending one or more attached documents. Scope of claims after amendment (1) High voltage and large current from a high voltage and large current source to a coaxial shunt via a test breaker. In a large current measuring device that supplies a bypass circuit breaker in parallel to the coaxial shunt, a switch connected in series to the coaxial shunt is provided, which works in conjunction with the bypass circuit breaker, and is connected in series to the coaxial shunt, allowing for precise measurement. What is claimed is: 1. A current measuring device, characterized in that only the current in the portion where the current is detected is detected from the coaxial shunt and is supplied to the measuring device, and the switch and the bypass breaker are simultaneously turned on and cut off by one operation system. (2) The current measuring device according to claim 1, characterized in that the switch and the bypass breaker are simultaneously turned on and cut off by a two-operation system using an operating device.

Claims (1)

[Claims] (11) A test breaker (Il-valve) is supplied from a high-voltage, large-current source to a coaxial shunt with a high-voltage, large current, and a bypass breaker is provided in parallel to the coaxial shunt. In the measuring device, a switch is provided in conjunction with the bypass breaker and connected in series to the coaxial shunt, so that only the current in the portion to be measured is detected by the coaxial shunt and supplied to the measuring device. , a current measuring device characterized in that the switch and the breaker for the bypass can be turned on and off at the same time with a single operation system. The 1!flow measuring device according to claim 1, characterized by a wire that simultaneously performs the blocking.