JPH09205724A - Ground fault distance relay - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a ground fault distance relay device that is not easily affected by a constant load current and can detect a ground fault accident in a wider range more quickly. SOLUTION: A voltage detecting means (33) for detecting a system voltage of its own end, a current detecting means (31) for detecting a current and a zero-phase current of its own line, and a negative phase for detecting a reverse phase current of its own line. Based on the current detecting means (32) and the current of its own line, the zero-phase current, the negative-phase current, and the system voltage of its own end detected by the respective detecting means, the negative-phase current is used as the polarity amount to determine the distance to the fault point. Ground fault accident point calculating means (34) for calculating, and accident determining means (34) for sending an opening command to the system breaker (21) on condition that the calculated distance to the accident point is within a predetermined range ( 35) and a ground fault distance relay device of a high resistance grounding system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective relay device which detects a ground fault in a transmission line of a high resistance grounding system and sends an opening command to a circuit breaker which separates a fault section.

[0002]

2. Description of the Related Art Various types of protective relay devices are used to protect transmission lines from various accidents. As one of them, for example, a ground fault direction relay device is known which, when a ground fault occurs in equipment in a high resistance ground system, isolates the fault point and protects it. FIG. 10 shows such a well-known ground fault direction relay device (hereinafter, referred to as a ground fault direction relay).

In the power system shown in FIG. 10, the power source 1
A power transmission line 12A is led out from an electric station A having 0A through a circuit breaker (CB) 11A to reach an electric station B.
A power transmission line 12B further extends from CB11B to the next electric station.

A current transformer (CT) 13A at the end A of the electric station
The own line current is detected by this, and the own transformer system voltage is detected by the voltage transformer (PT) 14A on the power transmission line 12A side. These detected currents and detected voltages are the protective relay device 1
5A is introduced into the ground fault direction determination means 16A, and the operation output of this determination means 16A is sent to the CB 11A as an opening command. As for electric station A, C is the same for electric station B
T13B, PT14B and protective relay device 15B are provided.

Now, paying attention to the electric station A, if a ground fault occurs at the accident point F of the transmission line 12A in the electric power system, the system current of the own line detected via the CT 13A and the PT 14A and the own end of the line. System voltage protection relay device 1
5A, zero-phase current I _o based on each captured data
1 and the zero-phase voltage V _o are detected, and the ground fault direction determining means 16A detects the zero-phase current I _o and the zero-phase voltage V _o .
The direction of the ground fault accident is determined based on the vector diagram of No. 1, and when the determined ground fault accident is located in the preset direction, the circuit breaker 11A is opened to disconnect the ground fault point F.

In the vector diagram shown in FIG. 11, the ground fault direction judging means 16A takes into account the phase difference θ between the detected zero-phase voltage V _o and zero-phase current I _o , and uses the zero-phase voltage V _o as a reference vector to achieve zero-phase. When the vector of the current I _o exceeds the judgment line P, that is, when it enters the operation range shown by the diagonal lines, it is judged as an accident and an operation output is issued.

However, with this method, the direction of the ground fault can be determined, but the distance from the relay device installation point (current transformer installation point) to the accident point F cannot be known. Therefore, in the event of a ground fault in the power system, the operating time of the ground fault direction relay installed at an electrical station closer to the power source end will be longer in order to keep the equipment outage within the minimum necessary range. , The time coordination is taken so that the operation time of the ground fault direction relay installed in the electric place farther from the power source end becomes shorter. For this reason, it has been necessary to allow the accident elimination to be delayed as the accident is closer to the power source end.

[0008]

As described above, in the ground fault protection relay device using the conventional ground fault direction relay for the transmission line of the high resistance ground system, the ground fault protection relay device has a ground fault in an electric station near the power source end. There was a problem that the detection of an accident was delayed. Especially in a high resistance grounding system, the ground fault current is smaller than the normal load current, and it is difficult to detect the fault current with high accuracy and identify the fault section by the ground fault direction relay.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a ground fault distance relay device which is hardly affected by a constant load current and which can detect a ground fault accident in a wider range more quickly and can identify a fault zone. To do.

[0010]

In order to achieve the above object, the invention of claim 1 sends a release command to a circuit breaker which detects a ground fault accident of a transmission line of a high resistance grounding system and separates the accident section. In the protective relay device, voltage detecting means for detecting the system voltage of the self end, current detecting means for detecting the current of the own line and zero-phase current, and anti-phase current detecting means for detecting the anti-phase current of the own line. , A reverse phase current based on the current of the own line and the zero-phase current detected by the current detection means, the reverse phase current detected by the reverse phase current detection means, and the system voltage of the self-end detected by the voltage detection means. Ground fault accident point calculation means for calculating the distance to the accident point as the amount of polarity, and an instruction to open the circuit breaker on condition that the distance to the accident point calculated by the ground fault accident point calculation means is within a predetermined range. Accident determination Characterized by comprising a stage.

Similarly, the invention of claim 2 is a ground fault distance relay device which detects a ground fault in a transmission line of a high resistance grounding system and sends an open command to a circuit breaker which separates a fault section. Voltage detecting means for detecting the system voltage, current detecting means for detecting the current of the own line and zero-phase current, and current difference detection for detecting the difference between the anti-phase current before the accident and the anti-phase current during the accident of the own line Means and the current of the own line and zero-phase current detected by the current detection means, the difference between the negative-phase current detected by the current difference detection means, and the system voltage of the self-end detected by the voltage detection means. Provided that the ground fault accident point calculating means for calculating the distance to the accident point using the difference between the phase currents as the polar amount and the distance to the accident point calculated by the ground fault accident point calculating means are within a predetermined range. Accident of sending open command to breaker Characterized by comprising a constant section.

According to a third aspect of the present invention, in the ground fault distance relay device according to the first or second aspect, the zero-phase voltage detecting means for detecting the zero-phase voltage at its own end and the zero-phase voltage detecting means detect the zero-phase voltage. Distance settling calculation means for changing the distance settling value in the accident determination means in accordance with the zero-phase voltage at its own end.

According to a fourth aspect of the present invention, in the ground fault distance relay device according to any one of the first to third aspects, a zero-phase current detecting means for detecting a zero-phase current of its own line and a zero-phase of its own end. Based on the phase relationship between the zero-phase voltage detecting means for detecting the voltage, the own-phase zero-phase current detected by the zero-phase current detecting means, and the own-end zero-phase voltage detected by the zero-phase voltage detecting means. And a ground fault direction determining means for determining the direction of the ground fault, wherein the accident determining means determines the release command transmission condition in consideration of the direction of the ground fault determined by the ground fault direction determining means. .

According to a fifth aspect of the present invention, in the ground fault distance relay device according to any of the first to third aspects, the difference between the zero-phase current before the fault of the own line and the zero-phase current during the fault is detected. Current difference detecting means, zero phase voltage detecting means for detecting the zero phase voltage at its own end, difference between zero phase currents detected by the current difference detecting means and phase of zero phase voltage detected by the zero phase voltage detecting means A ground fault direction discriminating means for discriminating the direction of the ground fault accident based on the relationship, and the accident discriminating means determines the release command sending condition in consideration of the direction of the ground fault accident discriminated by the ground fault direction discriminating means. It is characterized by

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, the present invention will be outlined with reference to FIG. The protective relay device according to the present invention can be used not only for protection of transmission lines but also for bus line separation and transformer protection. Here, an embodiment in the case of being used for protection of transmission lines will be described. .

In FIG. 2, a circuit breaker (C
B) The power transmission line 22 is led out via 21, and the other end of the power transmission line 22 is connected to the electric station B. The current transformer (CT) 23 detects the own line current on the side of the electric power station A of the circuit breaker 21, and the instrument transformer (PT) 24 detects the own line system voltage on the side of the power transmission line 22. These detected currents and detected voltages are introduced to a ground fault distance relay device (hereinafter referred to as a ground fault distance relay) 26 included in the protective relay device 25, and the operation output of this relay 26 is sent to the CB 21 as an opening command. It

FIG. 1 shows an embodiment of claim 1 according to the present invention. In the ground fault distance relay 30, the own line current detection means 31 detects the current I _p of the own line and the zero-phase current I _o based on the output current of the CT 23, and the own line anti-phase current detection means 32 detects the own line. The reverse-phase current I _n is detected. Further, the voltage detecting means 33 detects the phase voltage V _a at its own end based on the output voltage of the PT 24. Ground fault accident point calculation means 3 based on these respective detection outputs
4, the reactance X corresponding to the distance from the installation point of the relay 30 to the fault point is obtained by the following arithmetic expression with the negative-phase current I _n as the polarity amount. The arithmetic expressions are shown for the sake of convenience for theoretical explanation.

X = Y / Z (1)

[0019]

[Equation 1] I _m : Imaginary number I _n ^* : Conjugate complex number of I _n K: Zero phase compensation coefficient e ^{j φ} : Reference vector in the same direction as the transmission line impedance (setting value) The value of this reactance X is X _{1 as a} setting value. , X ≦
Whether it is within the range of X ₁ accident determining means 35 determines, determines that the internal fault if X ≦ X _1, CB2
A release command is sent to 1.

According to the embodiment shown in FIG. 1, the reactance X is used to obtain the ground fault distance, so that it is less susceptible to the load current at all times and the ground fault accident at the electric power station near the power source end is further reduced. It can be detected quickly.

FIG. 3 shows an embodiment of claim 2 according to the present invention. The own line current detecting means 41 and the voltage detecting means 43 in this ground fault distance relay 40 are the same as the detecting means 31 and 33 in the relay 30 of FIG. 1, and are respectively the phase current I _p and the zero phase current I _{o of the} own line.
Also, the phase voltage V _a at its own end is detected. The device of FIG. 3 is characterized by the detecting means 42 and the ground fault accident point calculating means 44.
The detection means 42 is a vector difference detection means for detecting the vector difference of the own-line negative-phase current, and according to the vector diagram shown in FIG. 4, the own-line negative-phase current I _nL before the accident and the negative-phase current I _nF during the accident. Based on and, the vector difference ΔI _n is calculated by the following arithmetic expression. Note that, here, for convenience, the display of the "dot" symbol of the meaning of the vector is omitted. ΔI _n = I _nF −I _nL (2) Based on each of these detection outputs, the ground fault accident point calculation means 44 sets the relay 40 by the following calculation formula using the negative phase current vector difference ΔI _n as the polarity amount. Find the positive-phase reactance X corresponding to the distance from the point to the accident point. X = Y / Z (3) where Y = I _m {(V _a · ΔI _n ^* )} Z = I _m {e ^{j φ} (I _p + K · I _o ) · ΔI _n ^* } I _m : Imaginary number min K: zero phase compensation coefficient ΔI _n ^*: ΔI _n complex conjugate I _n ^*: I _n the complex conjugate K: zero phase compensation coefficient e ^{j phi:} transmission line impedance in the same direction of the reference vector (set value) the positive The value of the phase reactance X is the same as in the case of FIG.
The X ₁ as setpoint, it is determined whether the range of X ≦ X ₁ accident determining means 45 determines that an internal accident if X ≦ X _1, sends an opening command to CB21 To do.
The system of this embodiment is suitable for a system in which the reverse phase current I _n is always large. When the phases of the anti-phase current I _nF during the accident and the anti-phase current I _nL before the accident are almost the same, even if the scalar difference is calculated instead of the vector difference in the vector difference detecting means 42, almost the same result is obtained. It is obvious that

According to this embodiment, as in the case of FIG. 1, the influence of the constant load current is less likely to occur, and the ground fault in a wider range can be detected more quickly.

FIG. 5 shows an embodiment of claim 3 according to the present invention. The ground fault distance relay 50 is provided with zero-phase voltage detection means 51, distance settling calculation means 52, ground fault accident point calculation means 53, and accident determination means 54.
Zero-phase voltage detecting means 51 detects the zero-phase voltage V _o of the local end on the basis of PT24 of the output voltage of Zidane. The distance settling calculation means 52 uses the zero-phase voltage V detected by the detection means 51.
_The distance settling value is changed according to _o , and when the zero-phase voltage V _o is low, that is, when the fault point resistance is large, the line drop voltage cannot be accurately obtained, which causes overreach of the distance relay. The unnecessary set-off situation may occur, so the distance settling value should be reduced to avoid it. The algorithm for the, for example, a distance setting value of K as a coefficient = reference value -K (100% zero-phase voltage value V _r - zero-phase voltage detection value V _o) ... may be set to (4).

The ground fault accident point calculation means 53 is an element 3 in FIG.
1 to 34, or distance calculation means composed of 1 to 34 or elements 41 to 31 of FIG.
It may have the same configuration as the distance calculation means composed of 44. The accident determination unit 54 determines that the internal fault is present if the calculation result of the ground fault accident point calculation unit 53 is within the settling value range obtained by the distance settling calculation unit 52.

Therefore, since the distance settling value is adjusted according to the magnitude of the zero-phase voltage, it is possible to prevent an unnecessary interruption due to a distance measurement error even if the accident has a large accident point resistance and to provide a highly reliable ground fault distance relay. Can be realized.

FIG. 6 shows an embodiment of claim 4 according to the present invention. Also in this ground fault distance relay 60, the ground fault accident point calculating means for calculating the distance to the ground fault accident point can be configured by the distance calculating means of FIG. 1 or FIG. 3 as in the embodiment of FIG. Here, it is characterized in that it is provided with means for discriminating the direction of the accident in order to prevent malfunction in a back accident. That is, in the embodiment of FIG.
A ground fault accident point calculation means 64 similar to the ground fault accident point calculation means 53 in FIG.
1. Zero-phase voltage detection means 62 and ground fault direction determination means 63
Is provided. The zero-phase current detecting means 61 detects the zero-phase current at the relay installation point based on the output of CT23, and the zero-phase voltage detecting means 62 detects the zero-phase voltage of its own end based on the output of PT24. The ground fault direction discriminating means 63 discriminates the ground fault direction based on the phase relationship between the zero phase current and the zero phase voltage detected by the zero phase current detecting means 61 and the zero phase voltage detecting means 62. The principle of discrimination is shown in FIG.
May be similar to that already described with reference to the vector diagram of FIG.

The ground fault accident point calculation means 64 determines that the distance to the accident point is within the set value, and its principle is the same as that of the ground fault accident point calculation means described with reference to FIG. 1 or 3. It can be the same. The accident determination means 65 determines that the internal fault occurs when both the ground fault direction determination means 63 and the ground fault accident point calculation means 64 generate an operation output, and the circuit breaker 21
An open command is sent to (Fig. 2).

FIG. 7 shows a fifth embodiment of the present invention. The ground fault distance relay 70 in this embodiment is also characterized in the ground fault direction determination as in the case of FIG. In this embodiment, the ground fault accident point calculating means 74, the zero phase voltage detecting means 72, the ground fault direction judging means 73 and the accident judging means 75, which are the same as those in FIG. 6, are provided and the zero phase current vector difference detection is performed. The feature is that the means 71 is provided.

The zero-phase current vector difference detecting means 71 is shown in FIG.
As shown in, the vector difference ΔI _o = I _oF −I _oL between the zero phase current I _oF during the accident at the relay installation point and the zero phase current I _oL before the accident is detected based on the output of _CT23. . Here, as in the case of the description of FIG. 4, the display of the “dot” code indicating the meaning of the vector is omitted. As can be seen from FIG. 9, the ground fault direction discriminating means 73 has a zero-phase current vector difference ΔI _o detected by the zero-phase current vector difference detecting means 71 and a zero at its own end detected by the zero-phase voltage detecting means 72. determine the direction of the accident from the phase relationship between the phase voltage V _o. The function of the ground fault accident point calculation means 74 is equivalent to that of the ground fault accident point calculation means 64 in FIG. The accident determination means 75 determines that the internal fault occurs when both the ground fault direction determination means 73 and the ground fault accident point calculation means 74 generate an operation output, and sends an open command to the circuit breaker 21.

The zero-phase current vector difference detection means 71 detects the vector difference between the zero-phase currents before and during the accident. If the phase difference θ between the two is zero or close to zero, the vector difference Obviously, the scalar difference may be taken instead. In that case, arithmetic difference detection is used instead of vector difference detection.

Therefore, according to the embodiment shown in FIGS. 6 and 7, by combining the direction determination with the distance determination by the distance measurement calculation, a highly reliable ground fault distance relay which does not malfunction due to a back accident is provided. Can be realized.

[0032]

As described above, according to the present invention, based on the current of the own line and the zero-phase current, the negative-phase current or the difference between the negative-phase current before and during the accident, and the system voltage at the self-end. ,
By calculating the distance to the fault point by using the negative-phase current or the difference between the negative-phase currents as the amount of polarity, even if the fault current is smaller than the normal load current, the fault point calculation can be performed with high accuracy. It can be carried out.

[Brief description of drawings]

FIG. 1 is a block diagram of a ground fault distance relay device according to claim 1 of the present invention.

FIG. 2 is a block diagram schematically showing a ground fault distance relay device according to the present invention.

FIG. 3 is a block diagram of a ground fault distance relay device according to claim 2 of the present invention.

4 is a vector diagram of an anti-phase current in the device of FIG.

FIG. 5 is a block diagram of a ground fault distance relay device according to claim 3 of the present invention.

FIG. 6 is a block diagram of a ground fault distance relay device according to claim 4 of the present invention.

FIG. 7 is a block diagram of a ground fault distance relay device according to claim 5 of the present invention.

8 is a vector diagram of zero-phase current in the apparatus of FIG.

9 is a diagram for explaining the principle of the ground fault direction determining means in the device of FIG.

FIG. 10 is a diagram for explaining a function of a ground fault direction relay device according to a conventional technique.

11 is a view for explaining the principle of a ground fault direction relay device in the device of FIG.

[Explanation of symbols]

21 Circuit breaker 22 Transmission line 23 Current transformer (CT) 24 Instrument transformer (PT) 25 Protective relay device 26, 30, 40, 50, 60, 70 Ground fault distance relay device (ground fault distance relay) 31 , 41 own line current detecting means 32 own line negative phase current detecting means 33, 43 voltage detecting means 34, 44, 53, 64, 74 ground fault accident point calculating means 35, 45, 54, 65, 75 accident judging means 42 own Line anti-phase current vector difference detecting means 51, 62, 72 Zero-phase voltage detecting means 52 Distance setting calculating means 61 Zero-phase current detecting means 63, 73 Ground fault direction judging means 71 Zero-phase current vector difference detecting means

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Makoto Sato 1-1-1, Shibaura, Minato-ku, Tokyo Inside Toshiba Headquarters Co., Ltd. Toshiba Fuchu Factory

Claims (5)

[Claims] Claim: What is claimed is: 1. In a protective relay device that detects a ground fault in a transmission line of a high-resistance grounding system and sends an open command to a circuit breaker that separates the faulty section, a voltage detection means that detects a system voltage at its own end. A current detecting means for detecting a current of the own line and a zero-phase current; a negative-phase current detecting means for detecting a reverse-phase current of the own line; and a current of the own line and a zero-phase current detected by the current detecting means, A ground fault that calculates the distance to the fault point by using the reverse-phase current as a polarity amount based on the reverse-phase current detected by the reverse-phase current detection means and the system voltage at the self-end detected by the voltage detection means. A point calculating means; and an accident determining means for sending an opening command to the circuit breaker on condition that the distance to the accident point calculated by the ground fault accident point calculating means is within a predetermined range. Characterizing Ground fault distance relay device resistance grounding system. 2. A protective relay device that detects a ground fault in a transmission line of a high-resistance grounding system and sends an open command to a circuit breaker that separates the faulty section, and a voltage detection means that detects a system voltage at its own end. A current detection means for detecting the current of the own line and a zero-phase current, a current difference detection means for detecting the difference between the anti-phase current before the accident and the anti-phase current during the accident of the own line, and the current detection means The difference between the opposite-phase currents based on the current of the own line and the zero-phase current, the difference between the opposite-phase currents detected by the current difference detection means, and the system voltage of the own end detected by the voltage detection means. Ground fault accident point calculation means for calculating the distance to the accident point as the amount of polarity, and the circuit breaker on the condition that the distance to the accident point calculated by the ground fault accident point calculation means is within a predetermined range. Accident sending a release command Ground fault distance relay device of the high-resistance grounding system, characterized in that a constant means. 3. A zero-phase voltage detecting means for detecting a zero-phase voltage at the self-end, and a distance set value in the accident determining means changed according to the zero-phase voltage at the self-end detected by the zero-phase voltage detecting means. The ground fault distance relay device of the high resistance grounding system according to claim 1 or 2, further comprising: 4. A zero-phase current detecting means for detecting a zero-phase current of its own line, a zero-phase voltage detecting means for detecting a zero-phase voltage of its own end, and a zero-phase current of the own line detected by said zero-phase current detecting means. A ground fault direction determining means for determining the direction of a ground fault accident based on the phase relationship between the zero phase current and the zero phase voltage at the end detected by the zero phase voltage detecting means; and the accident determining means, The ground fault distance connection of a high resistance grounding system according to any one of claims 1 to 3, wherein the opening command sending condition is determined in consideration of the direction of the ground fault accident determined by the ground fault direction determining means. Electrical equipment. 5. A current difference detecting means for detecting a difference between a zero-phase current before a fault of its own line and a zero-phase current during a fault, a zero-phase voltage detecting means for detecting a zero-phase voltage of its own end, and the current. A ground fault direction determining means for determining the direction of the ground fault accident based on the phase relationship between the zero phase current detected by the difference detecting means and the zero phase voltage detected by the zero phase voltage detecting means;
The high-resistance ground according to any one of claims 1 to 3, wherein the accident determination means determines the release command transmission condition in consideration of the direction of the ground fault determined by the ground fault direction determination means. System ground fault distance relay device.