JPS59212784A - Schering bridge circuit - Google Patents

Abstract

PURPOSE:To minimize the residual inductance of a Schering bridge circuit and improve the measuring accuracy, by using a shunt which has a large resistance value and is small in size as the shunt of the circuit and installing the shunt in the main body of the Schering bridge circuit together with an airtight case. CONSTITUTION:A shunt 13 which has a large resistance value and is small in size is prepared by putting the shunt 13 in an airtight case 16 equipped with a refrigerant inlet 14 and refrigerant outlet 15 and forcedly cooling the shunt 13 with an inter refrigerant, such as insulating liquid of insulating oil, etc., or inert gas of nitrogen gas, freon gas, etc. Then the shunt 13 is installed into the main body of a Schering bridge 9 together with the airtight case 16. When the Schering bridge 9 is constituted in such a manner, its residual inductance can be minimized and the tan delta error can also be reduced. Therefore, the mesuring accuracy can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a kneeling Britno circuit, and is particularly suitable for measuring the dielectric properties of dielectric materials such as insulators of ultra-high voltage, low loss power cables at commercial frequency high voltages with a high precision 71. It concerns the Schering-Blinozi circuit.

Figure 1 is a circuit diagram of the circuit of Yuzu Nerino Dublinon. In Figure 1, 1 is the gear under test. /ri,2
is a standard capacitor, 3 is a shunt consisting of a wire-wound resistor, 4 is a series resistor, 5 is a detector Flt meter, 6 is a transformer resistor, 7 is a variable capacitor, 8 is a series resistor, These are 12
Connect as shown. 11. \j indicates the commercial frequency control voltage.

By the way, in the conventional/kneeling Blitzkno circuit, consideration has been given to reducing the residual inductance of the current shunt 3, which is a part of its constituent elements, in order to reduce measurement errors. However, in order to reduce the temperature rise due to energization of the shunt 3 and -1, increase the long-term reliability of the resistance value, the shunt 3 must be made considerably large. Instead, the flow divider 3 is externally attached. However, in general, when a resistance element made of a wire-wound resistor has the same resistance value, the larger the element r is, the greater the residual inductance becomes. Will the length of the wiring become longer?7
When 11 qi v1 self hW or 1 value becomes 1, the measurement accuracy of the measuring instrument will be limited by the residual inductance, J+,..., Schiff, etc.).

・As2 diagram is an explanatory diagram of the configuration of the conventional /Kohli Noguri body. , branch flow Niji: (3 is a cylindrical) 11ν winding core 10 and has a configuration in which a rectangular M J no'+- wire 11 is wound in a folded manner, and 1-, It is a profit. 12 indicates a guard circuit.

Flow divider 3. υ・1n□rr
0mm circular winding core] It consists of 11 turns of 18111111 pitch winding on O, τ1, and resistance j1i0.1.
Ω, this shunt: 60 II Z when the ambient temperature is 20°C.

When a current is applied to 20, the temperature of Manganin Katsu 1 in the first rule rises to 60 degrees, and the rate of decrease in resistance due to this is 002.
%. The time constant of the resistance at this time is 0.88XIO-
It is 6 seconds. By the way, accommodating such a flow divider 3 in the main body 9 generates heat (40W).
This is impossible from the point of view of Svene and Svene, and as shown in FIG.

However, if it is connected to the outside, the time constant of the resistance including the residual inductance of the wiring is 1.15 x 10-6 seconds, and the tan i) Q'A difference is (1,
It becomes 043%.

The present invention has been made in view of the above, and its purpose is to provide a kneeling circuit that can reduce residual inductance and improve measurement accuracy.

A feature of the present invention is that a forced cooling means is provided for the shunt C, which is made of at least a wire-wound resistor that generates heat among the resistive elements constituting the circuit, and that the shunt is made small and has a large resistance value. - Built into the ring bridge main body, the structure is designed to reduce the residual inductance of the shunt and its wiring.

The present invention will now be described in detail using an embodiment shown in FIG.

FIG. 3 is an explanatory diagram of the construction of an embodiment of the two-circuit 9/Nielingutsu 9 circuit described in Book 5. In FIG. It is housed in the airtight case 16 that is being provided, and a flow divider 1:3 is used.
g * jA < or - Irregular gas, Lugeon gas, etc. 1 Step 1: Force the flow to flow with gas, use a shunt 13 with a large resistance value, or a small one, and use a shunt. The container 3 is built into the main body 9 together with the case 16.

In addition, the entire circuit diagram of the /Nielingtsu 9F2 circuit is shown in Part 1.
Same as the figure - (Yes.

Here, as shown in the figure, 0.2711771 X 4
m+++ length 54cm enamel-coated Mangani] wire (resistance 1 (σ0.3Ω))
0 nun, x 4.5 mm rectangular core 18 to 8
111111 Use the molecular tij vessel la constructed by wrapping it five times with L' notch, insert it into the airtight case 16, and put it in the airtight case 16 61 / /! If 20A is applied to the flow divider 13 with insulating oil flowing at a flow rate of 1.5 in, it will generate 120~■ heat, but Manganin Katsu] 7 c''M4 degrees can only be removed at a maximum of 40 degrees Celsius, The temperature rise of the insulating oil was 10° C. The airtight case 16 had outer dimensions of 100 x 40 x 20 mm.

Ushida / 03Ω built into the kneeling bridge body 9
The time constant of the shunt 13 rated at 2OA including the saw 1 wire section was 0.2X10-6 seconds, and the δ error at 6011Z was 0.0075 factors. This value is the same as that of the conventional flow divider 3.
This is a low value of about 17% of the tall δ error when using , and is an error that hardly causes any problem even when measuring t and I11 δ of a low-loss dielectric.

As mentioned above, according to the embodiment of the present invention, the flow divider X3
is housed in an airtight case 16 and forcibly cooled with a refrigerant, a small one with a large resistance value is used as the flow divider 13, and the flow divider 13 is built in the Schieri/Gublinosi body 9 together with the airtight case 16. I did this, so the lead
It is possible to reduce the residual '6'j i/ductance including the 1. line, reduce the Lftllδ error, and improve measurement accuracy. 1. Since it has a built-in flow divider, it is easy to handle.

In addition, in order to take advantage of the forced cooling effect of the flow divider 1; 3, fins are provided on the flow divider j3 and the structure of the winding core 18 is improved to make it 114! Even if the refrigerant is allowed to flow, no. In this way, the size can be further reduced, and the time constant can be reduced accordingly.

Earth, To, 1C Shita Real h (U In the example, a man attack line is used as a resistance limit, but a consta/tano line may also be used, and the effect is the same.

Insulation of resistance wire is not based on enamel coating,
Alternatively, the -C resistance wire may be insulated with a heat sink so that the -C resistance wire comes into direct contact with the refrigerant.

It's so good, it's small and thick in Figure 3! In the +1 chestnut, the branching device 1 is forced to cool the sea urchin, but other Nagasuke components are forced to cool down, including the resistor element, which has a problem.
It goes without saying that the cooling of '+1' may be done in any way, and that the entire kneeling bridge circuit may be forcibly cooled.

As explained above, the present invention has the effect that residual inductance can be reduced, -1,6 error can be reduced, and measurement accuracy can be improved.

[Brief explanation of drawings]

Figure i1 is a circuit diagram of a kneeling/kneeling circuit, Figure 2 is an explanatory diagram of the configuration of a conventional 7-ring circuit, and Figure 3 is an explanatory diagram of an embodiment of a seven-ring circuit of the present invention. It is. ] - Test gear / evening, 2 Standard code 7 design, 9 / Ni-ring bridge body, 13 - Flow divider, 16 Airtight coos, 17 - Enameled ↑ 9 Manganin wire, 18 - Rectangular winding core.ゝ、-／

Claims (1)

[Claims] 1. Dielectric property d11 of dielectric material at commercial frequency high voltage
In a 7-ring Blinozi circuit used for one constant, at least one of the resistance elements making up the circuit is measured. Of course I
Connected in series to the body? A forced cooling means for a shunt consisting of a wire-wound resistor is provided to divide the flow. For the resistor 2, use a small one with a large resistance 111'I,
The shunt is installed in the inner paper (7, the shunt pipe; φ and its wiring with a low θ・k of residual inductance, and there is a 4V'i structure inside the main body of the shunt ring).
1l - Strict/kneeling bridge circuit. zl) The forced cooling means includes an airtight case that houses the flow divider, and a supply of refrigerant fluid to the airtight case.
2. A kneeling circuit according to claim 1, comprising output means.