JPS59200974A - Device for measuring earthing resistance - Google Patents

Abstract

PURPOSE:To improve measuring accuracy by providing a means preventing the influence of floating potential to an earth potential measuring part in a device finding earthing resistance from constant current supplied to an earth network to be measured and its earth potential. CONSTITUTION:An oscillator 4 generating reference signals Acosomegat, Asinomegat is connected to a power supply 1 and a constant current amplifier 5 is connected to the output of the oscillator 4. Constant current is supplied from a constant current amplifier 5 to the earth network 7 to be measured through an ammeter 6 and a voltage measuring part 8 is connected between the earth network 7 and zero potential. The voltage measuring part is provided with a circuit multiplying two reference signals by a measured input respectively, adding values obtained by squaring respective multiplied values and then extracting the square root to remove a floating potential part from the measured input. Thus, precise earthing resistance can be calculated from the measured voltage of the voltage measuring part 8 and the measured current value of the ammeter 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grounding resistance measuring device δ that can be used to measure grounding resistance at ultra-high voltage transformers, switching stations, etc.

In extremely high-pressure situations, 5□n and 1 child are on the ground in order to ensure the safety of handling.

In this case, it must be ensured that such a close contact with the earth is possible.

For this reason, various types of measuring equipment have been used to measure the grounding resistance at a distance of 1 ft.

・α1 diagram is this single ground resistance 1H1] constant J
j ijl -re 1” indicates that the commercial frequency power supply AC (
-200V) at switch S1. Heats F, autotrans T, and e + 猷trans'l"2 are concubines,
The secondary winding side of this transformer T2 is connected to the VJJ switch S2.
Auxiliary grounding is provided via the same selector switch 82. The ground i+4N, which is the system to be measured, is connected through the cardiac flow meter A, and this key point rai N (!: Between zero potential ammeter A;
Calculate the resistance R by reading the indicated value 1'l + g2 of d New Year V when the switch 82 is turned to the left or right. It's straining.

In this case, the equipment is in operation! π Ni Chitte floating, Yu 4th place (
If I-O no Tosa 41 is the indicated value of New Year V) 5-Go, then the vector composition 159 shown in Figure 2 is established,
d and other resistances are determined from Crt.

In other words, the earth resistance ratio is the indicated value El +
IJ, , and floating 1.
It is well known that the Σ positions kD, , l are required to be calculated (this floating potential ICo not only fluctuates more easily than the ambient conditions Q but also lacks reproducibility, so the influence of the floating potential E. - The upper-level model, Yotomobi 1.'t, which was subjected to a large amount of damage, had the disadvantage of not being able to obtain accurate measurement results.

Therefore, in the past, in order to reduce the screwing force of the floating 4th place j9oo) Sugiharu, the flow hole in the first gauge A was made larger, but according to this, the trance-like dish was mischievously inserted into the dog. This not only makes the device larger, but also costs more than 111 hours.

When determining the ground resistance, it may be possible to temporarily stop the entire surface of the d or open i4'' points to eliminate the influence of the floating position Eo, but in this case,
'Since it is not easy to completely shut down the decommissioned substations and switchyards, it is necessary to reduce the grounding resistance to the level that will be required in the future during construction before the start of the expedition. It has the disadvantage that it requires revision.

This invention was made to eliminate the above-mentioned drawbacks.
Even if Morozoridou is still in the transfer state, if he receives the test of the floating potential Eo, then the resistance will be measured. The purpose is to provide

The first example of this series will be explained below with reference to the drawings.

In FIG. 3, 1 is a power supply, and this switch 2. The station 1 is connected to Tatsuura 4 via fuse 3. This emission jli gG 4 is Acos (lJt, As1
The single sign of nωt is outputted as the reference signal for ・1 and 2. At this time, the frequency ω of the signal is set to 1 at the maximum frequency of the line in order to reduce the error due to the frequency difference. Therefore, it is made to be slightly different from ω0.

77 (for example, the Teisho style amplifier 5) is connected to the output terminal 4, which is a violation.・It reads directly to the skin measurement system, for example, the grounding company 7, through the IT flowmeter 6, and the constant tonne current Icos (ωt-
I try to give a).

An L pressure measuring section 8 is connected between the grounding position 7 and the trough 1 as a calculation means. This ll'III constant part 8) is given the reference value lsii of the oscillation 44. in this case.

Measuring part 8 is 14! ; As shown in IJ, (1i11) As constant input V is given, the oscillation penalty 4 generates the 4-light signal Acosωt.

As1nωt is given separately to the power yy 811.8
12. Narrow-band low-pass filters 821, 822 to which the outputs X, y of these multipliers 811, 812 are given; squarers 831, 832, to which the outputs X, y of these low-pass filters 821, 822 are given; 831.
It has an adder 84:B that adds the outputs of the adders 832 and a squarer 85 that squares the outputs of the adders 84.

Next (explain the effect of this).

Now* From Haku 'r'a 4'44 m 'IN No. Ac
os6) t, As inωt is given by pressure measurement digital diagnosis 8f, and constant DC amplification 45 gives constant jα flow Icos (
Assuming that ω1-&) is given by polluting the hyphenmeter 6, then Ichikawa (Yoshikawa and 8 are floating as the measured human power V), cosωo1 and the sulfur measurement signal. IRcos
V = l(ocosωOt+1.t(ICO8(ωt-0)
) is υ et al. This 114il constant input ■) or multiplier 81
1.8121 is multiplied by 11 shells given by friends. Then, the multiplier 811 is obtained, and the multiplier 812 is obtained, n. And these outputs X+Y/)10-no-? When applied to filters 821 and 822, x, y
Of the items, only the free current component synchronized with the AC component force 5 is left, which is synchronized with the L overflow signal. RL (
X)2+(Y)',/Noy obtainedy'l, this7f1. If you calculate -C through the square rooter 85, the output will be 5, and
d flow meter 61 trowel can be sold directly, and A can be added to 1 meaning, so if A = 2, R, = JJ / I and the above instructions,! It is easier to get this out than U (
bawl.

Therefore, according to this theory, the AC component including the floating a position Eo is excluded, and the important point (measurement of the horizontal resistance R is required A +
u Only the necessary indicated value - can be calculated, so even if +tit is unlucky or wide, the floating type E can be used. It is possible to measure high resistance R without being affected by the effects of
]. It is possible to reduce the size of the device t by reducing the impact of C and increasing the transformer capacitance i + t. It is possible to suppress the upfront cost of returning costs to lower the resistance to the level that will be required in the future.

This publication is not limited to the above embodiments and may be modified as appropriate without changing the gist.

For example, in the above case, the voltage measurement unit 8
) Measurement of human power V (!: iii @ 4M No. Acosωt
, As1nωt are given to obtain x and y, but instead of this, the measuring human power V may be directly switched using a square wave of frequency ω. Furthermore, in the above-mentioned case, the low-pass filters 821 and 82 are used in the pressure measurement τIS8.
The output x, y of 2 is given to the adder 84 via 2=e831.832, and added to the square root AR,I unit 85 to obtain the shelf value -.
As shown in the figure, the output x, y 5: cosωt, si
Square wave ζ with nωt as the fundamental wave After switching each iron separately, add ml? ;, 9, where xcosωH-ysinωt = umma2.4-Ecos(ωt-cos-'-1 is obtained, and this I'1.W is passed through a bandpass filter 0 to obtain C. Furthermore, in the above description, the constant current output is obtained from the constant current width and the constant current. However, this output does not necessarily have to be an i-circular flow.

As described above, according to the present invention, even if the various equipments are left in the operating condition, they can remain floating. Cedar,, high 4'+ without receiving! f1. It is possible to provide a grounding resistance measuring device capable of determining the grounding resistance R (iill constant C).

[Brief explanation of drawings]

・Fig. f1 shows an example of a conventional one-dimensional measurement device for surface abrasions] A schematic purchasing diagram, Fig. 2 is a vector diagram for explaining the same device, and Fig. 3 is an example of the present invention. Figure 4 is a block diagram showing the pressure measuring port of the same ellipse, and Figure 85 is a schematic diagram showing another embodiment of the invention. It is a logical composition. 1°"' jt jt1 type 2...Switch 3...Heads 4...Emitting device 5...
Constant c4 flow width 6...=1<flow meter 7...ground wire 8...41 shirill constant part 811.81
2... Multiplier 82L, 822... Low pass filter 831.832... Square d juice 84.
9... black ri f < 议85...+Mqa
1'0...Band pass filter 11...Each 1st turn E2 EOE 3rd M

Claims (4)

[Claims] (1) oscillation means for generating first and second reference signals having frequencies slightly different from the commercial frequency and differing from each other by about 900 degrees; 7'L Convert this to 4 iL of constant amplitude and get 3
111 constant grounding system (current generating means to be applied, and floating level that causes pressure drop and commercial line skin failure due to the above current flowing through the grounding resistance of the grounding system to be measured). +1llJ constant 1,1 bow force S is applied Z% and the above first reference signal is applied to this measurement signal J,!:
; i, 1: a means for measuring and a self 4f for above-mentioned measurement signal;
It has a means for multiplying by two reference signals, and extracts only each DC component from each output of these two direct current components g.
1'Eg value is squared and added) γ and the square root square value is obtained) A concubine characterized by Kokichi with 7 means, iya resistance subequation: δ0 (2) The grounding resistor 1i11 fixed wire according to claim 1, wherein the ball amount α flow generating means comprises a fixed flow width amplifying device for generating a fixed flow. (3) The above-mentioned itching treatment means only direct current: v! ) J! , claim 1 = or claim 2, which includes the use of a low-pass filter with a low-pass filter. (4) Paragraph 1 of the patent claim, characterized in that the first stage of said 4-F has a squarer, an adder, and a squarer for squaring each of the DC component amplitudes. In any of the three sections above, I will be able to resist myself, my father, and my father.