JPH0650322B2 - Shock current measuring device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock current measuring device used for measuring shock current.

2. Description of the Related Art FIGS. 7 (A) and 7 (B) are explanatory views of a conventional Rogowski coil, and FIG. 7 (B) is provided with rewinding with respect to FIG.
The induced voltage along the great circumference is removed. The shield is omitted in FIG.

In FIG. 7, when the measured current passing through the closed curved surface is i, the output voltage E ₀ is calculated by the following equation.

Here, μ: permeability S: cross-sectional area of coil n: number of turns of coil l: length of coil C, R: integration capacitor and integration resistance CR The integration constant CR is determined by the pulse width of the measured current. ,
Select at least 10 times the normal pulse width.

Problems to be Solved by the Invention When the Rogowski coil shown in FIG. 7 is used and waveform observation is performed with a synchroscope, the output voltage E _{0 is} affected by noise.
Needs to be increased. When the shapes are the same, that is, the large radius and the cross-sectional area of the coil are the same, and the same integration constant is used, the number of turns of the coil is increased in order to increase the output voltage E ₀ . However, if the number of turns of the coil is increased, the length of the coil becomes longer, so that the response time becomes slower, and it becomes impossible to observe a fast phenomenon of, for example, nanosecond order.

Means for Solving the Problems The present invention eliminates the above-mentioned drawbacks, that is, a shock current measuring device, that is, an air-core coil wound on the same circumference is equally divided into a plurality of divided coils to form divided coils. A resistor for integration is inserted in each of them and these are connected in series, and a series circuit of the resistor and the capacitor for integration is inserted only at a predetermined one of them, and the voltage across the capacitor for integration is input to the waveform observing device. An impact current measuring instrument characterized by the above.
An air-core coil wound on the same circumference is equally divided into a plurality of divided coils to form divided coils, and an integrating resistor is inserted in each of the divided coils to connect them in series.
An opening is provided only at the location, one end of the integrating resistor connected to the final split coil is rewound to the first split coil, and the integrating capacitor is inserted to connect to the first split coil. It is intended to provide an impulse current measuring device characterized in that the voltage is inputted to a waveform observing device.

FIG. 5 is a circuit diagram of the principle of the shock current measuring device of the present invention. 1 is a split coil arranged on the same circumference (8 split coils divided into 8 in the figure), 2 is serial to each split coil 1. The connected integrating resistor 3 is an integrating capacitor connected in parallel to the series circuit of the split coil 1 and the integrating resistor 2,
1 with split coil 1, integrating resistor 2 and integrating capacitor 3
5 sets are formed, and FIG. 5 is composed of 8 sets.

FIG. 6 shows two sets taken out in FIG.
In FIG. 1A, the inductance values L ₁ and L ₂ of the split coils 1 and ₁ , the resistance values R ₁ and R 2 of the integrating resistors 2 and ₂ ,
When the capacitance values C ₁ and C _{2 of the} integrating capacitors 3 and 3 are equal to each other (L ₁ = L ₂ , R ₁ = R ₂ , C ₁ = L
₂ ) will form a bridge circuit, as shown in FIG.
Is equivalent to FIG.

Therefore, in FIG. 5, the inductance values L ₁ , L ₂ , ... Of the split coils 1, ₁ ,.
... resistance values R ₁ , R ₂ ..., integration capacitor 3,
When the capacitance values C ₁ , C ₂ ... Of 3 ... Are equal to each other, it is equivalent to FIG.

In FIG. 1, m divided coils 1 are arranged on the circumference of a radius r, and the measured current passing through the circumference is i, the output voltage E ₀ is calculated by the following equation.

Here, N: the number of turns of the split coil per S: S: sectional area of the split coil μ: permeability C, R: integration capacitor and integration resistance

Function The characteristics of the shock current measuring device of the present invention using the conventional Rogowski coil and the split coil will be compared.

In a conventional Rogowski coil having a coil wound at a pitch P and a radius a on the circumference of a radius r, and a shock current measuring instrument of the present invention using a split coil obtained by dividing the coil by m, the propagation time T in the coil is Is calculated by the following equation.

The propagation time T _R of the conventional Rogowski coil The propagation time T _C of the shock current measuring device of the present invention is Here, C: speed of light is shown.

Therefore, the impact current measuring device of the present invention using a coil divided into m has a propagation time of 1 / m when the number of turns is the same, that is, the same output, as compared with the conventional Rogowski coil. This means that when comparing coils having the same response time, the output voltage can be increased m times.

Embodiments Next, the shock current measuring device of the present invention will be described with reference to the embodiments shown in FIGS.

FIG. 2 is a circuit diagram of an embodiment, in which an air-core coil wound on the same circumference is equally divided, eight divided coils 1 are arranged, and an integrating resistor 2 is connected in series to each divided coil 1. Then, only a predetermined one of them is connected in series by inserting a series circuit of an integrating resistor 2 and an integrating capacitor 3 to form a closed circuit, and both ends of the integrating capacitor 3 are connected to a waveform observing device. The terminal 5 is provided, and the split coil 1, the integrating resistor 2, and the integrating capacitor 3 are shielded 4 to remove the induced voltage along the radius r.

FIG. 3 is a circuit diagram of another embodiment, in which an air-core coil wound on the same circumference is equally divided and eight divided coils 1 are arranged, and an integrating resistor 2 is connected in series to each divided coil 1. The first division coil 1 is rewound by rewinding one end of the integration resistor 2 connected to the final division coil 1 to the first division coil 1 and inserting the integration capacitor 3 into the first division coil 1. Terminals 5 connected to the split coil 1 to form a closed circuit and connected to the waveform observing device at both ends of the integrating capacitor 3.
Where the opening 6 is removed in order to eliminate the induced voltage along the radius r, that is, the split coil 1, the resistor 2, which corresponds to the unwinding portion at one end of the integrating resistor 2 connected to the final split coil 1, The integrating capacitor 3 is shielded 4.
When the opening 6 is provided as shown in FIG. 3, the split coil 1 is wound without cutting the current circuit to be measured, and the current can be easily observed.

FIG. 4 is a sectional view taken along the line AA ′ in FIG. 2, showing the shielded state of the split coil 1 and the integrating resistor 2. The split coil 1 is shielded so as not to form a short-circuit ring with respect to the coil axis. The integrating resistor 2 is completely shielded.

Effect of the Invention When comparing the conventional Rogowski coil of the present invention, when the shape, that is, the cross-sectional area, the number of turns, and the integration constant are the same, the impact current measurement of the present invention is clear as is clear from the above formula (4). The propagation time of the vessel is 1 / m of the propagation time of the conventional Rogowski coil, and fast response characteristics can be obtained. Further, in the case of the conventional Rogowski coil, the resistance of the coil is determined by the resistance of the winding, so the ring impedance appears in the output waveform because the surge impedance of the coil is very small, but in the case of the shock current measuring instrument of the present invention, the split coil Since the integration resistor is inserted in the, the resistance value is selected, and the non-vibration condition is obtained, so that there is an advantage that ringing is eliminated. Therefore, there is an effect that it is possible to measure a nanosecond-order fast phenomenon, which has been considered to be difficult in the past, and it is of great industrial and practical value.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a shock current measuring device of the present invention, FIG. 2 is a circuit diagram of an embodiment of a shock current measuring device of the present invention, and FIG. 3 is another embodiment of a shock current measuring device of the present invention. FIG. 4, FIG. 4 is a sectional view taken along the line AA ′ in FIG. 2, FIG. 5 is a circuit diagram of the principle of the shock current measuring device of the present invention, and FIG. 6 (A) is a schematic diagram for explaining the principle. 5 is a circuit diagram showing a part of FIG. 5, FIG. 6 (B) is an equivalent circuit diagram of FIG. 6 (A), and FIGS. 7 (A) and 7 (B) are explanatory diagrams of the Rogowski coil. 1: split coil, 2: integration resistor 3: integration capacitor, 4: shield 5: terminal, 6: opening

Claims (1)

[Claims] 1. An air-core coil wound on the same circumference is equally divided into a plurality of divided coils to form divided coils, and an integrating resistor is inserted in each of the divided coils to connect them in series to form a closed circuit. Forming or further rewinding the closed circuit in the middle to form an opening, and inserting a series circuit of an integrating resistor and an integrating capacitor only in a predetermined one of them to form a waveform of the voltage across the integrating capacitor. An impact current measuring device characterized by being configured so as to input to an observation device.