JP2003319549A - Distribution line accident section locator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distribution line accident section locator capable of detecting an accurate accident position and the direction without affected by a grid condition or a transient response due to the accident pattern. <P>SOLUTION: Accident detectors distributed along the distribution line are inputted with a zero-phase voltage and a zero-phase current at an arrangement point from a zero-phase voltage sensor and a zero-phase current sensor. By judging the sign of an electric quantity (power product) of two vector products for a prescribed period, before and after occurrence of earth fault, the earth fault direction is accurately determined without affected by a grid condition, an accident pattern, etc. Thus, an accident direction is accurately detected without affected by the grid condition or a transient response due to an accident pattern. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for locating a ground fault accident section when a ground fault occurs on a power distribution line, and in particular, eliminates erroneous determination due to differences in power distribution system conditions, accident aspect, etc. The present invention relates to a ground fault accident section locating device characterized by performing accident section locating.

[0002]

2. Description of the Related Art As a conventional ground fault accident section orientation, a phase difference between a zero-phase voltage and a zero-phase current is calculated in a Petersen coil ground system as shown in Japanese Patent Laid-Open No. 2001-28833, and this phase difference is calculated. There is known a ground fault accident section locating system that detects a ground fault with high accuracy by determining the accident direction based on the polarity of, and setting the frequency region in which the phase difference is calculated to be equal to or higher than the resonance frequency of the system.

Further, as disclosed in Japanese Patent Application Laid-Open No. 7-87662, an accident is caused by the change in the magnitude of the zero-phase voltage and zero-phase current generated by the detector slave stations distributed on the power distribution line. A ground fault detection processing system that supplements information, determines the occurrence of a ground fault from the information, polls the information stored in the detection slave station memory, and determines the ground fault section based on the information is known. There is.

[0004]

As a ground fault accident direction detecting method as in the above conventional method, a conventional protection relay for determining the phase difference of the zero phase current with respect to the zero phase voltage and simply determining the sign of the phase difference. In the conventional determination method, there is a possibility that an erroneous determination may be made due to the influence of the transient response when a ground fault occurs in an accident situation in which a ground fault current flows intermittently, such as a discharge ground fault.

Further, in a ground fault detection processing system that collects accident information from a conventional detection device by polling and determines a ground fault section based on the information, a single polling procedure for collecting information is used. Since the accident information of all the arranged detection devices is collected, the information of the detection device that does not contribute to the ground fault section determination is also collected, and the transmission efficiency is poor and the load of the information collection source device is large. .

[0006]

In order to achieve the above object, the present invention provides a zero-phase voltage at a disposition point, a zero-phase voltage from a zero-phase current sensor, a zero-phase voltage and a zero-phase in an accident detection device distributedly arranged on a distribution line. By inputting a current and determining the sign of the electric product (power product) obtained by taking the product of two vectors in the predetermined period before and after the occurrence of the ground fault, the influence of the system condition, accident aspect, etc. Therefore, the ground fault direction is determined without making an erroneous determination.

Further, when collecting the accident information detected by the detecting device, the accident information of the detecting device at the end of the substation side is first collected, the ground fault occurrence distribution line is specified from the collected accident information, and then the It is characterized in that necessary detection device information is efficiently collected by sequentially polling each detection device on the distribution line from the end of the distribution line.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an accident section locating device according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram of the entire system which is an embodiment of an accident section locating device.

In FIG. 1, 1 is a power source behind the power distribution system and 2
Reference numerals a and 2b denote distribution lines.

In such a distribution system configuration, a distribution line breaker 3 is provided near the most power source of the distribution line (substation sending section).
a, 3b and voltage / current sensors 41a, 41b are arranged. Distribution switches on the distribution line are distributed switches 4
a and 4b, and voltage / current sensors 40a to 40h installed at the above-mentioned division switch arrangement points, and detect zero-phase voltage and zero-phase current. The accident information calculation unit 11a to
11h and the accident detection devices 10a to 10h including the communication control units 12a to 12h are arranged. Similarly, a substation accident detection device 20 including an accident information calculation unit 21 and a communication control unit 22 is installed in the voltage / current sensor of the distribution line breaker of the substation sending unit. These accident detection devices are dedicated detection devices, or substation devices and slave station devices of the distribution automation system that are already installed have accident information calculation units 11a to 11a.
It can be realized by incorporating h and 21. Each accident information detection device is connected via a communication transmission line 50 to an accident section orientation calculation device 30, which is a higher-level device. The accident section location calculation device can be realized by incorporating a calculation function and a communication function into a dedicated device or an existing higher-level device of the distribution automation system, like the accident information detection device.

FIG. 2 shows a detailed internal functional diagram of the accident detection device 10. The accident detection device 10 includes a voltage / current input calculation unit 100 for inputting signals from a voltage / current sensor, and an input calculation unit 1.
The calculation result of 00 is used as an input, and the accident information calculation unit 110 for calculating the accident information and the zero-phase voltage calculation result of the input calculation unit 100 are used as inputs to perform a zero-phase voltage change width calculation, determine an accident, and output an accident information calculation start signal. Vo change width calculation unit 13
0, an accident information determination unit 120 and a communication control unit 140 that transmits accident information.

Before explaining the operation of the apparatus, a ground fault accident aspect in a non-grounded system or a reactor grounded system (called Petersen coil ground: PC ground) will be described. FIG. 3 shows a simplified distribution system configuration for explanation. The distribution system is a high impedance primary side with a limiting resistance Rn and a reactor Ln connected to the open terminal of the third open triangular connection of the grounding transformer 5 or the grounding transformer 6 which is independent for each substation bank. It has a structure in which the sex point is grounded.
The case where the ground impedance is only the limiting resistance Rn is called a non-ground system, and the cases where the ground impedance is Rn and Ln are called a reactor ground system. In such a distribution system, F of the distribution line 2
When the ground fault of the ground fault resistance Rg occurs at the point, the ground fault current If
Sensor 1 and sensor 2 on both sides of the accident point F
, A zero-phase current of Io1 and Io2 is generated. FIG. 4 shows an equivalent circuit at the time of a one-wire ground fault at point F of the distribution system in FIG. In the equivalent circuit of FIG. 4, Io1 and Io2 are expressed by the following equations (1) and (2), respectively.

Io1 = − (1 + j (ωC1-1 / ωLn) · Rn) Vo / Rn (1) Io2 = jωC2 · Vo (2) As can be seen from the above equations (1) and (2), the accident point F The zero-phase current Io1 detected by the sensor 1 on the power source side has an effective component due to Rn and an invalid component due to C1 and Ln, whereas the zero-phase current Io detected at the sensor 2 on the load side from the point F
o2 is only an invalid portion due to C2. Also, the zero-phase voltage V
It can be seen that o detects the same zero-phase voltage in the sensors 1 and 2. That is, the zero-phase voltage at the time of the ground fault is the ground fault current I flowing through the ground impedance independent for each substation bank.
Since it is determined by f, the same value is obtained at any detection point in the substation bank. Now, unify the polarities of the voltage and current sensors,
When the vector product (electric power product) of the zero-phase voltage and the zero-phase current is taken, the electric power product sign indicates an active component when it is positive and an inactive component when it is negative. Therefore, by determining the sign of this power product, it can be determined whether the accident point is on the power supply side or the load side with respect to the detection point. The sign of this power product is exactly as described above in the static state (steady state), but in the transient state when a ground fault occurs, it shows a constant value due to the influence of distribution line impedance and ground impedance. There is no such thing.

FIG. 5 shows a result of experimentally obtaining a power product pattern when a ground fault occurs. In FIG. 5, 115 indicates a power product at a detection point on the power supply side of the ground fault point, and 116 indicates a power product at a detection point on the load side of the ground fault point. The power product 115 at the detection point on the power supply side shows both positive and negative values according to the time elapsed from the occurrence of the ground fault, whereas the power product 116 at the detection point on the load side from the ground fault point is There is a change in the absolute value with the lapse of time after the occurrence of the fault, but all are in the negative region. The response of the electric power product 115 is an effect of the above-mentioned transient response, and in the simple comparison of the settling level and the detected value as in the case of the conventional protection relay, it may be a factor to be erroneously determined depending on the transient response difference determined by the system condition and the appearance of the accident. . Therefore, in order to determine the accident direction from the calculated electric power product, if it is determined that the electric power product signs are all negative in all the regions of the predetermined determination periods 125 and 126, the above-mentioned transient response is not affected, and it is accurate. Accident direction can be determined.

The length of the predetermined determination period can be arbitrarily changed according to the situation such as the system configuration of the distribution line.

The operation of the entire apparatus when a ground fault occurs at point F in FIG. 1 will be described according to the operation flow in FIG. Each sensor distributed on the distribution line detects zero-phase voltage and current due to ground fault. In each accident information detection device that uses the sensor output as input, the zero-phase voltage from the sensor changes at any detection point in the bank in the same way due to the occurrence of a ground fault. At the same time, determine the occurrence of an accident. The accident information calculation unit is activated by the accident occurrence determination, and each detection device processes the accident information calculation (power product calculation) to determine each accident direction. The calculated accident information is stored in the internal memory and stored until polled by the host device. The fault zone orientation calculation device 30, which is a higher-level device, receives the fault information of the substation fault detection device 20 by the fault occurrence information interrupt signal from the substation fault detection device 20, and determines from the received information that the ground fault occurred bank concerned. Determine the distribution line. In this embodiment, the information is collected by the accident occurrence information interrupt signal from the substation accident detection device 20, but this can also be realized by the information collection method by the periodic polling of the accident section orientation calculation device. After determining the ground fault accident distribution line, the accident section orientation calculation device 30 sequentially polls from the end of the distribution line of the accident detection device distributed and arranged on the distribution line, and receives the accident information. In the section determination, when the information from at least two accident detection devices is received, the accident section is located by comparing the accident directions in the received information. If the accident direction in the received accident information is opposite, it is determined that the section sandwiched by the accident detection device is a ground fault section, and if it is in the same direction, the next accident detection device is polled and the accident information is polled. Is received and the same section determination is performed.

According to this embodiment, the ground fault occurrence distribution line is determined to be the distribution line 2a from the accident information of the substation accident detection device 20, and the minimum polling of the accident detection devices 10d, 10c and 10b is performed. By doing so, it is possible to locate an accident section, which improves transmission efficiency and simplifies information collection compared to the conventional method of polling and collecting information from all devices, and the information collection processing of the accident section orientation calculation device 30 which is the information collection source device. The load can be reduced.

[0019]

Since the present invention is constructed as described above, there is an effect that the accident position and direction can be accurately detected without being affected by the transient response due to the system condition or the accident aspect. Then, in the accident information collection, the bank where the accident occurred and the distribution line are first determined, and then the information on the accident detection device on the accident distribution line is collected, so that the transmission efficiency can be improved and the information collection can be simplified. This has the effect of reducing the information gathering load of a certain accident segment location device.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a detailed configuration diagram of the accident information detection device of FIG.

FIG. 3 is a diagram illustrating a ground fault accident aspect.

FIG. 4 is a diagram showing an equivalent circuit of FIG.

FIG. 5 is a simulation example of a power product pattern in the event of a ground fault.

FIG. 6 is an overall operation flow showing an embodiment of the present invention.

[Explanation of symbols]

2a, 2b ... Distribution line, 3a, 3b ... Distribution line breaker, 4
a to 4h ... Distribution line section switch, 10a to 10h ... Accident detection device, 11a to 11h ... Accident information calculation unit, 12a to 1
2h, 22 ... Communication control unit, 20 ... Substation accident detection device,
21 ... Accident information calculation unit, 30 ... Accident section orientation calculation device,
40a-40h, 41a, 41b ... Voltage / current sensor, 5
0 ... Communication transmission line.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G033 AA01 AB02 AC02 AD13 AD16                       AD18 AF03 AF05 AG14                 5G058 EE01 EF03 EH01

Claims (4)

[Claims] 1. A zero-phase voltage sensor and a zero-phase current sensor are dispersedly arranged on a power distribution line, and a calculation device for calculating a ground fault accident direction with a sensor installation point as a reference by using the sensor output as an input, Equipped with a calculating means for determining the occurrence of a ground fault by the zero-phase voltage change width, the vector product of the zero-phase voltage and the zero-phase current at the time of ground fault is calculated in a predetermined period before and after the start determination,
A distribution line fault section locator characterized by determining the direction of a ground fault by determining the sign of the vector product within a predetermined period. 2. Accident information from an accident detection device having a zero-phase voltage sensor, a zero-phase current sensor and a calculation function for performing accident detection calculation using sensor signals as inputs, and a communication means with a host device. In the distribution line accident section locator equipped with a means for collecting the information, the information of the accident detection device near the substation of the distribution line is collected to identify the distribution line where the ground fault has occurred, and the substation from the end on the distribution line. A distribution line accident section locating device characterized by locating an accident section by sequentially collecting accident information from an accident detection device in the given direction. 3. A zero-phase voltage and a zero-phase current are input from a zero-phase voltage sensor and a zero-phase current sensor distributed on a distribution line, and the sign of the electric quantity (electric power product) obtained by taking two vector products is grounded. By determining the sign of the power product in a predetermined period before and after the occurrence of the
A distribution line accident section locator designed to determine the location of a ground fault. 4. When collecting accident information detected by a detection device having a zero-phase voltage and zero-phase current sensor, the detection device accident information at the end of the substation side is first collected, and the ground information is collected from the collected accident information. A distribution line fault section locating device characterized by collecting necessary detection device information by identifying a distribution line and then sequentially polling each detection device on the distribution line from the end of the distribution line. .