JPH0510632B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a ground fault point locating device for two parallel circuits in a power system.

[Prior art]

As fault point locating devices for power systems, there are methods such as applying shock waves and using fault surges.
It is already known that there are devices that utilize traveling waves.

However, since the traveling wave must pass through a coupling device in order to be applied to or received from the power transmission line, it has the disadvantage that the device is complicated and expensive.

[Summary of the invention]

This invention was made for the purpose of eliminating the drawbacks of the conventional ones, and provides a device that measures the distance to the fault point from the fault current and fault voltage generated in the power system in the event of a one-line ground fault. do.

[Embodiments of the invention]

Figure 1 shows a power system with two parallel circuits.
1 is the power supply, 2 is the transformer, 3 is the neutral point resistor, 4 is the bus bar, 5 is the first line of the parallel two-line system, 6 is the second line, 7 is the bus bar, 8 is the transformer, 9 is the neutral point resistance, 1
0 is the load, 11 is the fault point, 12 is a transformer that derives the zero-sequence voltage component, 13 and 14 are current transformers that derive the zero-sequence current components of line 1 and line 2 of the parallel two-circuit system, and 100 is this transformer. 1 shows a ground fault point locating device which is an embodiment of the invention.

Figure 2 is a diagram showing symmetrical branch circuits when a one-wire ground fault occurs at fault point 11 in Figure 1, where 21 is a positive phase circuit, 22 is a negative phase circuit, 23 is a zero phase circuit, and 24
and 25 indicate current transformers placed at the installation point of the failure point locating device 100, which correspond to the current transformers 13 and 14 in FIG. Further, the symbols in the figure are as follows.

E: Power supply Zs ₁ : Positive sequence impedance behind _{the power} transmission side Zs ₂ : Negative sequence impedance behind the power transmission side Z ₂ : Anti-sequence impedance per unit [Km] of the 2-parallel line part Z _pA : Zero-sequence impedance per unit [Km] of the 1st line part of the 2 parallel lines _pB : Unit of the 2nd line part of the 2 parallel lines [ Km] Zero-sequence impedance per kilometer Z _R1 : Positive-sequence impedance behind the receiving side Z _R2 : Negative-sequence impedance behind the receiving side X _TR Zero-sequence impedance behind the receiving side R: Load impedance Rg: Fault point resistance 3R _NS : Power supply side Neutral point resistance 3R _NR : Neutral point resistance on the receiving side x: Distance from the installation point of the fault point locating device to the fault point [Km] L: Length of two parallel lines [Km] Z _n : Unit [Km] ] Mutual impedance between lines I ₀₁ : Zero-sequence current of line 1 of parallel two-circuit system I ₀₂ : Zero-sequence current of line 2 of parallel two-circuit system I _F : Fault point current V ₀ : Installation of fault point locating device Zero-sequence voltage at a point FIG. 3 shows in detail the mutual impedance between lines in the zero-sequence circuit of FIG. 2. In figure 3
If we _set Z _{R0 =}

V _O = xZ _pA I _p1 + xZ _n I _p2 + (L-X)Z _n I _p2 + (L-
x) Z _pA (I _p1 - I _F ) + Z _Rp (I _p1 + I _p2 - I _F )...Equation (1) Similarly, the following equation (2) holds true on the Line 2 side.

V _p =xZ _n I _p1 +LZ _pB I _p2 + (L-x)Z _n (I _O1 - I _F ) +Z _Rp (I _p1 + I _p2 - I _F ) ...Equation (2) Next, equation (1) and ( 2) The solution procedure for finding the distance x to the failure point from equation 2 will be explained.

From equation (1), the following equation (11) holds true.

I _F = (LZ _pA + Z _Rp ) I _p1 + (LZ _n + Z _Rp ) I _p2 −V _p /LZ _p
A +Z _Rp -xZ _pA = A/B - xZ _pA ... (11) formula However, A = (LZ _pA +Z _Rp ) I _p1 + (LZ _n + Z _Rp ) I _p2 -Vo = A ₁ + A ₂ - _{V p} or less For convenience of explanation, A ₁ = (LZ _pA + Z _Rp ) I _p1 and A ₂ = (LZ _n + Z _p2 ) I _p2 .

B=LZ _pA +Z _Rp .

Furthermore, equation (12) holds true from equation (2).

I _F = (LZ _n + Z _Rp ) I _p1 + (LZ _pB + Z _Rp ) I _p2 −V _p /LZm
+Z _Rp -xZ _n =C/D-xZ _n ...Equation (12) However, C = (LZm + Z _Rp ) I ₀₁ + (LZ _pB + Z _Rp ) I _p2 -V _p = C ₁ + C ₂ -V _p For convenience, C ₁ = (LZ _n + Z _Rp ) I _p1 and C ₂ = (LZ _pB + Z _Rp ) I _p2 .

D=LZ _n +Z _Rp .

Here, since equations (11) and (12) are equal, the distance x to the failure point can be determined using the following equation (3).

x=AD-BC/ _AZn -CZ _pA = _Q1 / _Q2 ...Equation (3) However, for convenience of the following explanation, _Q1 =AD-BC and _Q2 = _AZn -CZ _pA .

In equation (3 ₎ , A, B, C, and D are the power system constants ( _{L, Z pA , Z Rp ,} Since Z _n , Z _pB ) are known, it can be seen that the distance x to the failure point can be found.

Equation (3) is a method for measuring the fault point distance when a ground fault occurs in Line 1 of a parallel two-line system, but when a fault occurs in Line 2, it is the same as the failure in Line 1. Considering this, the following equation (4) holds true on the Line 1 side.

V _p = xZ _n I _p2 + LZ _pA I _p1 + (L - x) Z _n (I _p2 - I _F ) + Z _Rp (I _p1 + I _p2 - I _F ) ...Equation (4) Similarly, on the Line 2 side, the following Equation (5) holds true.

V _p =xZ _pB I _p2 +xZ _n I _p1 +(L-x)Z _n I _p1 +(L-
x) Z _pB (I _p2 - I _F ) + Z _Rp + I _p1 + I _p2 - I _F )...Equation (5) Furthermore, from Equation (4), the following Equation (21) holds true.

I _F =E/F-xZ _n ...Equation (21) However, E = (LZ _n + Z _Rp ) I _p2 + (LZ _pA + Z _Rp ) I _p1 - V _p F = LZ _n + Z _Rp .

Furthermore, the following equation (22) holds true from equation (5).

I _F =G/H-xZ _pB ...Equation (22) However, G = (LZ _pB + Z _Rp ) I _p2 + (LZ _n + Z _Rp ) I _p1 - V _p H = LZ _pB + Z _Rp .

Here, since equations (21) and (22) are equal, it can be seen that the distance x to the failure point can be determined using the following equation (6).

x = FG - EH / GZ _n - EZ _pB ...Equation (6) Fig. 4 is a block diagram showing a ground fault fault point locating device according to an embodiment of the present invention, and shows a state in which a ground fault has occurred in Line 1. It shows.

In the figure, 101 is the power transmission end (bus 4, i.e.
102 is an input terminal for inputting the zero-sequence voltage V _p of line 1 5 (fault line side) in the two parallel lines; 103 is an input terminal for inputting the zero-sequence current I _p1 of line 1 5 (fault line side) Input terminal for inputting zero-sequence current I _p2 of line 2 6 (healthy line side) in two parallel lines, 104 is zero-sequence impedance of line 1 5
LZ _pA is the impedance on the receiving end Z _Rp (zero-sequence impedance behind the receiving side X _TR and neutral point resistance on the receiving side
105 is an arithmetic circuit (first arithmetic circuit) that adds the mutual impedance LZ _n between the two parallel lines and the receiving end impedance Z _Rp (the second arithmetic circuit ₎ . circuit), 106 is an arithmetic circuit (third arithmetic circuit) that adds the receiving end side impedance Z _Rp to the zero-sequence impedance LZ _pB of line 2 6, and 107 is the arithmetic result of the arithmetic circuit 104 and the zero-sequence current of line 1 5 An integration circuit (first integration circuit) that integrates I _p1 , 108 is the calculation result of the calculation circuit 105 and the zero-sequence current of line 2 6
Integration circuit that integrates I _p2 (second integration circuit), 10
9 is an integration circuit (third integration circuit) that integrates the calculation result of the calculation circuit 105 and the zero-sequence current I _p1 of line 1 5;
110 is an integration circuit (fourth integration circuit) that integrates the calculation result of the calculation circuit 106 and the zero-sequence current I _p2 of line 2 6; 111 adds the integration result of the integration circuit 107 and the integration result of the integration circuit 108; An addition/subtraction circuit (first addition/subtraction circuit) 112 subtracts the zero-phase voltage V _p at the power transmission end from the added value; An addition/subtraction circuit (second addition/subtraction circuit) that subtracts the zero-phase voltage V _p of an arithmetic circuit (fourth arithmetic circuit) for subtracting the value obtained by integrating the arithmetic results of 104; 114;
is the value obtained by integrating the calculation result of the addition/subtraction circuit 111 and the mutual impedance Z _n between lines per unit length, and then calculates the calculation result of the addition/subtraction circuit 112 and the zero-sequence impedance Z _pA per unit length of line 1 5. an arithmetic circuit that subtracts the integrated value (fifth arithmetic circuit);
115, the calculation result of the calculation circuit 113 is sent to the calculation circuit 1;
A division circuit that divides by the integration result of 14, 200 is 1
Ground fault fault point locating device for Line 5, 201 is the output terminal of the ground fault fault point locating device 200, 300 is the ground fault fault locating device for Line 2 6, 301 is the output terminal of the ground fault fault point locating device 300 , 400 is a changeover switch, and 500 is a final output terminal.

Next, the operation will be explained.

The ground fault fault location device 200 for Line 1 calculates the distance to the fault point by calculating equation (3). In the arithmetic circuit 104, L (length of two parallel lines [Km]), Z _pA (zero-sequence impedance per unit [Km] of line 11), Z _Rp (zero-sequence impedance X _TR behind the power receiving side and Calculate the impedance obtained by adding neutral point resistance 3R _NR ) and calculate B=LZ _pA +Z _Rp in equation (11).
get.

The arithmetic circuit 105 calculates L, Z _n (inter-line mutual impedance per unit [Km]) and Z _Rp (12)
Obtain the formula D=LZ _n +Z _Rp .

The arithmetic circuit 106 calculates L, Z _pB (zero-sequence impedance per unit [Km] of line 2) and Z _Rp , and outputs LZ _pB +Z _Rp .

The integrating circuit 107 integrates I _p1 (zero-sequence current of line 1) and B and outputs A ₁ =(LZ _pA + Z _Rp ) I _p1 of equation (11).

The integrating circuit 108 integrates I _p2 (zero-sequence current of line 2) and D and outputs A ₂ =(LZ _n +Z _Rp ) I _p2 of equation (11).

The integration circuit 109 integrates I _p1 and D to obtain the equation (12).
Output C ₁ = (LZ _n + Z _Rp ) I _p1 .

The integrating circuit 110 integrates I _p2 and the output of the arithmetic circuit 106 and outputs C ₂ =(LZ _pB +Z _Rp ) I _p2 of equation (12).

Addition/subtraction circuit 111 adds V _p , A ₁ and A ₂ to
Output A=A ₁ +A ₂ −V _p in equation (11).

Addition/subtraction circuit 112 adds V _p , C ₁ and C ₂
Output C=C ₁ +C ₂ −V _p in equation (12).

The calculation circuit 113 calculates A, B, C and D.
Output Q ₁ =AD−BC in equation (3).

The arithmetic circuit 114 calculates A, C, Z _n and Z _pA and outputs Q ₂ =AZ _n -CZ _pA of equation (3).

The division circuit 115 divides Q ₁ by Q ₂ to output x=Q ₁ /Q ₂ of equation (3), and outputs the distance to the ground fault point of line 1 to the output terminal 201.

Further, the ground fault fault point locating device 300 determines the fault point location of line 2 using equation (6) in the same way as the idea of line 1, and outputs the result to the output terminal 301.

Figure 4 shows the situation when a failure occurs in Line 1. When a failure occurs, a failure detector (not shown) using a protective relay or the like detects whether the failure is in Line 1 or Line 2. When line 2 is out of order, the changeover switch 400 is configured to be connected to the upper side in the drawing (when line 2 is out of order, it is configured to be connected to the lower side in the drawing). As a result, the distance x to the fault point of line 1 shown in equation (3) is the final output terminal 50.
Output to 0.

If a failure occurs in Line 2, the fault detector connects the changeover switch 400 to the lower side on the drawing, so the distance to the failure point of Line 2 shown in equation (6) becomes the final output 500. It will be output.

In this way, according to the above embodiment, the distance to the fault point can be measured using the fault current and fault voltage when the fault occurs.

In the above example, two fault point locating devices were installed for line 1 and line 2, and after calculation, the calculation result on the fault circuit side was derived by the response of the fault detector. It goes without saying that the arithmetic processing within the locating device may be switched between the one for line 1 and the one for line 2, and the arithmetic processing may be performed by one failure point locating device.

〔Effect of the invention〕

As described above, according to the present invention, the power system is configured to measure the distance from the fault current and fault voltage to the fault point when a fault occurs.
This has the effect of making the device simple and inexpensive.

[Brief explanation of the drawing]

Figure 1 shows a power system with two parallel circuits;
The figure shows a symmetrical branch circuit when a one-wire ground fault occurs in Figure 1, Figure 3 shows the zero-phase circuit in Figure 2 in detail, and Figure 4 shows one implementation of this invention. 1 is a diagram illustrating a ground fault point locating device according to an example; FIG. In the figure, 101 is the V _p input terminal, and 102 is the V p input terminal.
I _p1 input terminal, 103 is I _p2 input terminal, 104 to 106 are arithmetic circuits, 107 to 110 are integration circuits, 111, 112 are addition/subtraction circuits, 113, 11
4 is an arithmetic circuit, 115 is a division circuit, 201 is an output terminal, 301 is an output terminal, 400 is a changeover switch, and 500 is an output terminal. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first arithmetic circuit that adds the power receiving end side impedance to the zero-sequence impedance of the faulty line in the two parallel lines, and a second arithmetic circuit that adds the power receiving end side impedance to the mutual impedance between the lines of the two parallel lines. circuit, a third arithmetic circuit that adds the impedance on the receiving end side to the zero-sequence impedance on the healthy line side in the two parallel lines, and integrates the arithmetic results of the first arithmetic circuit and the zero-sequence current on the faulty line side. a first integration circuit that integrates the calculation result of the second calculation circuit and the zero-sequence current on the healthy line side, and a second integration circuit that integrates the calculation result of the second calculation circuit and the zero-sequence current on the faulty line side a third integrating circuit that integrates the phase current; a fourth integrating circuit that integrates the calculation result of the third integrating circuit; a fourth integrating circuit that integrates the zero-sequence current on the healthy line side; and the integrating result of the first integrating circuit and the above. A first addition/subtraction circuit that adds the integration results of the second integration circuit and subtracts the zero-sequence voltage at the power transmission end from the added value, and an integration result of the third integration circuit and the fourth integration circuit. a second addition/subtraction circuit that adds the results and subtracts the zero-sequence voltage at the power transmission end from the added value;
From the value obtained by integrating the calculation result of the first addition/subtraction circuit and the calculation result of the second calculation circuit, the second
a fourth arithmetic circuit that subtracts the sum of the arithmetic results of the adder/subtracter circuit and the arithmetic result of the first arithmetic circuit; a fifth calculation circuit that subtracts a value obtained by integrating the calculation result of the second addition/subtraction circuit and the zero-sequence impedance per unit length on the faulty line side from a value obtained by integrating the impedance; An earth fault failure point locating device comprising: a division circuit that divides the calculation result of the circuit by the calculation result of the fifth calculation circuit.