JP2002139538A - Base point terminal selection method for multiple-port fault point locating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make selectable the optimum terminal having a largest trouble phase current as a base point terminal, and to locate accurately a fault point of both circuits by an impedance method, regardless of the power flow direction and magnitude of a current between each terminal of a transmission line, when dual-circuit in-phase one-line ground is generated in the multi-port parallel dual-circuit transmission line. SOLUTION: In base point terminal selection of this multiple-port fault point orientation device, when in-phase one-line ground of circuits L1, L2 is generated, either of terminals α, β is selected as the base point terminal based on measurement information of the currents and the voltages of each terminal α, β of the multi-port parallel dual- circuit transmission line 1, and the distance from the base point terminal to the fault point where a trouble of the circuits L1, L2 is generated is operated by the measurement information of the current and the voltage of the base point terminal and an impedance characteristic of the transmission line 1. In this method, respective absolute values of each phase current in each circuit L1, L2 are determined relative to each terminal α, β, and the sums of the absolute values of all the phase currents in the circuits L1, L2 are operated, and the terminal corresponding to the maximum sum selected therefrom is selected as the base point terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-terminal parallel two-line power transmission line, in which a two-line in-phase one-line ground fault occurs, one of the terminals is selected as a base end, and an impedance system is used to detect the failure of both lines. The present invention relates to a method of selecting the base end in a multi-terminal fault locator (multi-terminal fault locator) for locating a fault point that has occurred.

[0002]

2. Description of the Related Art In general, in a system of two parallel transmission lines, when a ground fault or short circuit accident occurs, a fault point at which the accident occurred is quickly searched and necessary measures are taken promptly. This is important from the viewpoint of preventing the spread of failure.

[0003] With the development of digital relays using microcomputers in recent years, this type of transmission line fault location is replaced by a conventional pulse radar type or surge receiving type fault location device. Therefore, a digital fault locating device using the digital relay is often used.

[0004] This digital fault locating device is a self-terminal type that is applied to a single-ended power supply system, and voltage and current information of each terminal of a parallel two-line transmission line are collected at one place. In the case where the multi-terminal type fault point locating device is provided in a system of a parallel two-line transmission line with a single-ended power supply, the multi-terminal type fault locating device is formed as shown in, for example, a single-line diagram in FIG.

In the parallel two-line power transmission line 1 shown in FIG. 3, one terminal α is connected to a three-phase power source 2 having a neutral point resistance ground to form a power source side terminal, and the other terminal β is connected to a load. 3 are connected to form a load-side terminal, and each phase voltage at the terminals α and β is measured by the instrument transformer 4 at the terminals α and β.

A circuit breaker 5 and an instrument current transformer 6 are provided at both ends of each of the two lines L ₁ and L ₂ between the terminals α and β.
The current transformer 6 measures each phase current of the lines L ₁ and L ₂ .

Further, a digital fault locating device is formed by the collection / operation unit 7 of the terminal α and the collection unit 8 of the terminal β.

The data collection device 9α of the unit 7
Is the voltage measurement information of the transformer 4 at the terminal α, and the line L at the terminal α
₁ , L ₂ , current measurement information of each current transformer 6, line L ₁ ,
L ₂ of the information of the opening and closing state of the terminal α-side breaker 5 (breaker information) and based on the fault detection collecting trip command, etc. These circuit breakers 5.

The data collection device 9β of the unit 8
Is the voltage measurement information of the transformer 4 at the terminal β, and the line L at the terminal β
₁ , L ₂ , current measurement information of each current transformer 6, line L ₁ ,
Based on breaker information and fault detection of the terminal β-side circuit breaker 5 of the L ₂ collecting trip command, etc. from the protective relay of the circuit breaker 5 (not shown).

[0010] The two data collection devices 9α and 9β
Each of them has a function of various digital relays such as a distance relay of control device number "44S" and a ground fault directional relay of the same number "67G". The operation of these digital relays based on current and voltage measurement information, Under the condition that the trip command is input, the occurrence of an accident on the transmission line 1 is detected, and the current,
Collect and hold voltage measurement information.

When a data collection device is installed at the load end, even if an accident occurs, the distance relay and the ground fault direction relay may not operate. Has the function of an undervoltage relay having the control device number "27" and a function of a ground fault overvoltage relay having the same number "64". The current and the voltage can be obtained by the operation of one of the relays of the "27" and "64". It is preferable to collect and hold the measurement information.

After detecting the occurrence of the accident, the detected information and the current and voltage measurement information held by the data collection devices 9α and 9β are transmitted from the data collection devices 9α and 9β to the arithmetic unit 10 of the unit 7. Sent by wire or wirelessly.

Although the arithmetic unit 10 may be provided on either side of the terminals α and β, here, the unit 7 on the terminal α side
It is provided in.

Then, the arithmetic unit 10 executes the set orientation calculation program, and conventionally operates as shown in FIG. 4 based on the reception of accident detection information.

[0015] That is, when it is determined the occurrence of an accident in the step S ₁ of the drawing, to determine from the relay information included in the received information in step S _2, the operation of the relay "44" is a short circuit, When only the “67G” relay operates, it is determined that a ground fault has occurred.

If the fault point is located by calculating the distance (impedance) from the terminal having the largest current to the fault point, it is considered that the positioning error is minimized. Conventionally, the terminal 10 selects the terminal having the largest zero-phase current among the terminals as the base end.

[0017] That is, when determining that a ground fault in step S _2, the step S _3, based on the measurement information of the current data collection device 9.alpha, vector sum of the two lines L _1, the zero-phase current of L ₂ of the terminal α (Absolute value), and the magnitude (absolute value) of the vector sum of the zero-phase current of both lines L ₁ and L ₂ of the terminal β is calculated based on the measurement information of the data collection device 9β.

More specifically, as shown in FIG. 3, an in-phase one-line ground fault occurs in the lines L ₁ and L ₂ , and the zero-phase current I ゜_01α flows from the terminal α to the fault points 1φG ₁ and 1φG _2. , I ° _02α flows, the fault point from the terminal β 1φG _1, the 1FaiG ₂ zero-phase current I
° _01Beta, when flow I ° _02Beta, in step S _3,
For the terminal α, the absolute value of the vector sum | I _{01α + I _{}
02 alpha} | computes, for terminal β is the absolute value of the vector sum | computing the | I ° _01β + I ° _02Beta.

It should be _{noted that} the _{circles at} the right shoulder of the zero-phase currents I ゜_{01α to} I ゜_02β are symbols indicating that they are vectors, and so on.

Then, | I ゜_01α + I ゜_02α |> | I ゜
_{If 01β} + I ゜_02β |, the larger terminal α is selected as the base end.

On the other hand, when a short circuit accident is determined, the terminal at which the sum current of the lines L ₁ and L ₂ of the respective phase currents of the terminals α and β is the largest is selected as the base end.

[0022] That is, when determining that short circuit in step S _2, the step S _4, based on measurement information of the current data collection device 9.alpha, the vector sum of the two lines L _1, L ₂ of each phase current of the terminal α The absolute values are obtained by calculation, and the vector sum of both lines L ₁ and L ₂ of each phase current at the terminal B is calculated based on the current measurement information of the data collection device 9B to obtain their absolute values.

Then, the terminal of the largest one of the absolute values of the vector sum, for example, the terminal α is selected as the base end.

Specifically, the three phases of the transmission line 1 are represented by A, B, C
And the line L on the terminal α side₁Each phase current of I ゜_A1α, I ゜
_B1α, I ゜_C1α, Terminal L side line L_TwoEach phase current of I ゜
_A2α, I ゜_B2α, I ゜_C2αSimilarly, the rotation on the terminal β side
Line L₁, L_TwoEach phase current of I ゜ _A1β, I ゜_B1β, I
゜_C1β, I ゜_A2β, I ゜_B2β, I ゜_C2βThen the terminal
The magnitude (absolute value) of the sum current of each phase on the α side | I ゜_A1α+ I
゜_A2α|, | I ゜_B1α+ I ゜ _B2α|, | I ゜_C1α+ I ゜
_C2α|, ... and the magnitude of the sum current of each phase on the terminal β side
| I ゜_A1β+ I ゜_A2β|, | I ゜_B1β+ I ゜_B2β|, |
I ゜_C1β+ I ゜_C2βAnd calculate the largest of these
Terminal is selected at the base end.

Next, when selecting a base point terminal at Step S ₃ or step S _4, the step S _5, base terminal of the current, based on the information and the impedance information of the transmission line 1 voltage, in orientation calculation of the impedance method fault point is base end, for example, from terminal α 1φG _1, fault point 1FaiG ₁ seeking distance X to 1φG _2, Standardize 1φG _2.

Specifically, in the case of a ground fault, the following equation 1
The distance X is calculated and calculated from the orientation formula of (1).

[0027]

(Equation 1)

In the case of a short-circuit accident, the distance X is obtained by calculating the distance X from the same equation as in Equation 1 in which the zero-phase current is replaced by the line current.

[0029]

In the case of the above-described conventional multi-terminal fault locating apparatus, the method of selecting a base end using zero-sequence current, as shown in FIG. If the system is connected to the grounded power supply 11, both lines L ₁ ,
When phase 1 line ground of L ₂ occurs, the following problems.

That is, the capacity of the power supply 2 in FIG.
A, it is assumed that the capacity of the power supply 11 is 100 A, and the current flow direction is from the terminal β to the terminal α as shown by an arrow in the figure based on the load distribution and the like of the transmission line 1.

In this state, when an in-phase one-line ground fault occurs on the lines L ₁ and L ₂ , the neutral point ground resistance of the power source 2 is reduced by the power source 11.
And the magnitude (absolute value) of the vector sum of the zero-phase current is | I ｜ _0A1 + I ゜_0A2 |> | I ゜
_0B1 + I ゜_0B2 |, and the terminal α is larger than the terminal β. Therefore, in the conventional method, the terminal α is always selected as the base end.

However, the fault current (phase current) due to the ground fault is limited by the neutral point grounding resistance of the power supplies 2 and 11, and depending on the direction and magnitude of the power flow, the fault current at the terminal α becomes the load current in the power flow direction. In the opposite direction, the magnitude becomes almost the same, and a situation occurs in which the measured fault phase current becomes extremely small.

Therefore, when the terminal α is used as a base end,
When the distance X is obtained from the calculation of the following equation, the A / D
The conversion bit error and the calculation error greatly affect the calculation of the distance X, and there is a problem that the localization accuracy of the fault point P is significantly reduced.

In a multi-terminal type fault point locating device provided on a multi-terminal parallel two-line transmission line having three or more terminals, if a two-line in-phase one-line ground fault occurs on the transmission line, a fault point is determined by an impedance method. In the case of orientation, the same problems as described above occur.

The present invention relates to a multi-terminal type fault locating device provided for a transmission line of this type, in which an in-phase one-line ground fault (two-line in-phase one-line ground fault) occurs in both lines of the transmission line. Regardless of the direction and magnitude of the current flow between the terminals of the transmission line,
An object of the present invention is to make it possible to select an optimum terminal having the largest fault phase current as a base end, and to accurately locate a fault point by an impedance method.

[0036]

In order to solve the above-mentioned problems, a method of selecting a base end of a multi-terminal type fault locating apparatus according to the present invention comprises the steps of: Based on the measurement information, when an in-phase one-line ground fault occurs on both lines of the transmission line, one of the terminals is selected as the base end, the current and voltage measurement information at the base end, and the transmission line impedance characteristics By calculating the distance from the base end to the fault point at which the ground fault of both circuits occurred, when selecting the base end of the multi-terminal fault point locating device that locates the fault point of both circuits by the impedance method, For each line, calculate the absolute value of each phase current for each line, calculate the sum of the absolute values of all phase currents of both lines, and set the terminal corresponding to the largest of the sums of the absolute values to the base end. Select.

Therefore, when a two-line in-phase one-line ground fault of the transmission line occurs, the absolute value of each phase current is determined for each line for each terminal of the transmission line, and the absolute value of all the phase currents of both lines is determined. Calculate the sum of the values (scalar sum of all phase currents).

The scalar sum of the above-mentioned all-phase currents at each terminal is larger at the terminal β than at the terminal α when, for example, a power flow in the direction of the arrow in FIG. 2 occurs.

Since the terminal at which the scalar sum of all the phase currents is the largest is selected at the base end, the fault phase current measured at the base end is determined by the bit error or the calculation regardless of the direction and magnitude of the power flow. The error is large enough to be ignored, and the fault point is accurately located by the impedance method by the calculation of the equation (1) without being affected by these errors.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. As shown in the single-line diagram of FIG. 2, in the case of this embodiment, the transmission line 1 has one terminal α connected to a power supply 2 having a neutral point resistance grounding of a capacity 300A and the other terminal β connected to a neutral capacity 100A. Power supply with point resistance ground 11
Connected to. In FIG. 2, the same reference numerals as those in FIG. 3 denote the same or corresponding components.

The current flow direction of the two lines L ₁ and L ₂ of the transmission line 1 is from the terminal β to the terminal α as shown by the arrow in the figure.

In this state, if an in-phase one-line ground fault occurs in the lines L ₁ and L ₂ , the data collection devices 9α and 9β detect the occurrence of the fault in the transmission line 1 and measure the current and voltage in the same manner as in the prior art. Collect and retain information.

Thereafter, the information is transmitted from the data collection devices 9α and 9β to the arithmetic device 10 by wire or wirelessly, and the arithmetic device 10 executes the set orientation calculation program.

The program for the orientation calculation is different from the conventional one, and the arithmetic unit 10 operates as shown in FIG.

That is, the occurrence of an accident and the ground fault / short circuit are determined in steps Q ₁ and Q _{2 in} FIG. _{1 in} the same manner as in steps S ₁ and S _{2 in} FIG.

[0046] Further, determination time of ground fault by step Q _3, the received "44S", from the information of the circuit breaker 5 of the operation information and trip command of the digital relay such as "67G",
It is determined whether the two lines L ₁ and L _{2 have} the same-phase one-line ground fault or the one-line one-line ground fault of the line L ₁ or L ₂ .

When a two-line in-phase one-line ground fault occurs on the lines L ₁ and L ₂ , the process shifts from step Q ₃ to step Q _4. , The magnitude (absolute value) of each phase current of each of the lines L ₁ and L ₂ is calculated, and the sum of them (scalar sum of all phase currents) is calculated.

Specifically, on the terminal α side, a scalar sum of all phase currents (| I ゜_A1α | + | I ゜_A2α | + | I ゜
_B1α | + | I ゜_B2α | + | I ゜_C1α | + | I ゜_C2α |)
_Is calculated, and a scalar sum of all phase currents (| I ゜_A1β | + | I ゜_A2β | + | I ゜_B1β | + | I _}
B2β | + | I ゜_C1β | + | I ゜_C2β |) is calculated.

That is, for each terminal n of the transmission line 1, the scalar sum of all the phase currents (| I ゜_{A1 n} | + | I ゜_A2n
| + | I ° _B1n | + | I ° _B2n | + | I ° _C1n | + | I
゜_C2n |) is calculated.

Next, the terminal corresponding to the largest one of the scalar sums of all the phase currents of each terminal is selected as a base end.

More specifically, the terminal α or the terminal β corresponding to the direction in which the scalar sum of the all-phase currents on the terminal α side and the scalar sum of the all-phase currents on the terminal β side are larger is selected as the base end.

In this case, if the power flow direction is from terminal β to terminal α as shown in FIG. 2, when an accident occurs, both lines L ₁ ,
L load current flow direction to flow toward the respective phases ₂ from the terminal beta to the terminal alpha, for fault phase, terminal alpha, fault point from β 1φG _1, the fault current flows toward the 1FaiG ₂ in addition to the load current .

[0053] Therefore, the terminal alpha, in both lines L _1, L ₂ of the beta, the respective phase currents are measured I ° _{A1 alpha,} I ° _B1arufa, I °
_C1α ,..., I ゜_A2β , I ゜_B2β , I ゜_C2β are the largest on the terminal β side of the accident phase, and the terminal α of the accident phase
The side one is the smallest.

Therefore, when discriminated by the conventional method using zero-phase current, | I ゜_01α + I ゜_02α |> | I ゜_01β + I
゜_02β |, and the terminal α is erroneously selected as the base end. In the case of the present embodiment, (| I ゜_A1α | +... +
| I ゜_C2α |) <(| I ゜_{A1 β} | +... + | I ゜_C2β
|), The optimum terminal β having the largest fault phase current is selected as the base end.

[0055] After selection of the base end, in the orientation calculation equation of the impedance mode of the number 1 in the step Q ₅ in FIG. 1, for each line L _1, L _2, a fault from the terminal β which is selected as a base point end point 1φG _1, fault point 1FaiG ₁ seeking distance X to 1φG _2, and orientation of 1φG _2, outputs the orientation results to the control unit and the display device terminates the orientation in step Q _6.

In this case, regardless of the direction and size of the tidal current,
Since the terminal having the largest fault phase current is always selected as the base end, the fault points 1φG ₁ and 1φG ₂ can be accurately located.

If the transmission line 1 is a single power supply terminal system shown in FIG. 3, each phase current always flows from the terminal α to the terminal β. Therefore, even with the selection method of the present invention, the fault phase current is maximized. The terminal α is selected at the base end.

Next, upon the occurrence of a 1 line 1 line ground fault of the line L ₁ or line L ₂ is, per each phase current, in order to sneak the current to the accident has occurred from the healthy line failure circuit occurs In the method of obtaining the scalar sum of all the phase currents,
The sneak currents are also added to cause a mistake in selecting the base end.

[0059] Therefore, when one line 1 line earth fault line L ₁ or line L ₂ is generated, the process proceeds from step Q ₃ of FIG. 3 in step Q _7, although computation load than the impedance method increases, the difference current The fault point is located by the shunt ratio method.

This differential current shunt ratio method is described in Nissin Electric Technical Report V
oL. 43, NO. 2 (issued in '98 .9) P. 2
5-33, as described in the specification of Japanese Patent Application Laid-Open No. 5-223883, the distance from each terminal to the fault point is obtained based on the line-to-line difference current and the section length between the terminals. In the case of this method, the fault point can be located without any problem such as the wraparound, regardless of which terminal is used as the base point end.

[0061] Further, upon occurrence of a short circuit accident, the process proceeds from step Q ₂ in FIG. 1 in step Q _8, selects the base end in the same manner as Step S ₄ in FIG. 4, then, in step Q _5, The fault point is located by the impedance method.

Therefore, in the case of this embodiment, when a two-line in-phase one-line ground fault of lines L ₁ and L ₂ occurs, an accident occurs regardless of the direction and magnitude of the current flow between terminals α and β. precisely fault point impedance manner by selecting the phase current largest optimum terminal base end 1FaiG _1, it is possible to locating the 1φG _2, 1 line 1 line earth fault only line L ₁ or line L ₂ In addition, even in the event of a short circuit, the failure point can be accurately located by an optimal method.

In the above embodiment, the two terminals α and β
The present invention is applied to the selection of the base end of the multi-terminal fault locating device provided on the transmission line 1 of the present invention. Of course, the present invention can be applied to the selection.

[0064]

The present invention has the following effects. In-phase 1-line ground fault of both lines L ₁ and L ₂ of transmission line 1 (2
When the line phase 1 line earth fault) occurs, the terminals of the transmission line 1 alpha, for each beta, line L _1, L ₂ separate phase currents each of the two lines L ₁ and the absolute value, L ₂ The sum of the absolute values of all the phase currents (scalar sum of all phase currents) is calculated, and the terminal having the largest scalar sum of all phase currents is selected as the base end. Regardless of the direction and magnitude of the current flow of each phase current, the optimal terminal with the largest fault phase current can be selected at the base end, and based on this selection, the fault point can be accurately located by the impedance method Can be.

[Brief description of the drawings]

FIG. 1 is a flowchart of a fault point locating according to one embodiment of the present invention.

FIG. 2 is a single-line diagram of a transmission line on which the fault location of FIG. 1 is performed.

FIG. 3 is a single-line diagram of a transmission line of a single-ended power supply.

FIG. 4 is a flowchart of a conventional fault point location.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 2 parallel transmission lines 2, 11 Power supply 7 Collection / operation unit 8 Collection unit 9 _α , 9 _β data collection device 10 Operation device L ₁ , L ₂ line

Claims (1)

[Claims] 1. When an in-phase one-line ground fault occurs in both lines of the transmission line based on measurement information of current and voltage of each terminal of the multi-terminal parallel two-line transmission line, one of the terminals is disconnected. Based on the current and voltage measurement information at the base end, and the impedance characteristics of the power transmission line, the distance from the base end to the fault point at which the ground fault of the two lines has occurred is calculated, When selecting the base point end of the multi-terminal type fault point locating apparatus for locating the fault points of the two lines by the impedance method, for each of the terminals, obtain the absolute value of each phase current for each line and obtain the absolute value of each of the two lines. Calculating the sum of the absolute values of the phase currents, and selecting the terminal corresponding to the largest one of the sums of the absolute values as the base end, selecting the base end of the multi-terminal type fault point locating device. Method.