JPH0847165A - Bidirectional protection relaying system and bidirectional protection distance relay in the power line - Google Patents

Abstract

PURPOSE:To confirm the position power failure point in the power line system by judging whether a failure occurs in the front or rear side of the power distribution line of the installation point of the distance relay depending on the positive or negative sign of the reactance value measured when the failure occurs and then coordinating the operation time limit of the distance relay. CONSTITUTION:The power sources 42, 42 are connected at both sides of the power distribution line 12 and digital distance relays 14a, 14b, 14c, 14d, 14e of which resistance values up to the failure point 16 can compute and judge the reactance values are provided for each switch 38 provided to the points A, B, C, D, etc., of the power distribution line 12. For instance, if the grounding failure occurs at the intermediate point 16 of the points B and C of the power distribution line 12, position of failure point 16 is judged using the operation characteristic diagram 44. The switches 38, 38 provided in parallel in the distance relays 14c, 14b in the shortest distance for the failure point 16 open. As a result, the failure point in the power failure section can be confirmed and power failure can be recovered quickly by minimizing the range of power failure section.

Description

Detailed Description of the Invention

The present invention relates to a bidirectional protective relay system and a bidirectional protective distance relay in an electric line of a power system.

[0002]

2. Description of the Related Art Conventionally, various protective relays have been used to protect electric lines and devices of an electric power system, and when a fault such as short circuit, grounding or disconnection occurs at any point of the electric line, a fault current or Abnormal voltage is detected by the protective relay and the switch is opened promptly to protect the load side of the electric line and the equipment.

For example, as shown in FIG. 5, as an electric line,
A tree-type electric line in which distribution lines are branched from the main line in accordance with the distribution of load is widely used because it can cope with an increase in load demand and maintenance is easy. In the fault protection of this tree-type electric line, if there is a grounding accident at point F1 between AB, the line is installed close to point A and the line is monitored from point A to point B. The distance relay Za operates by detecting the failure of F1, and the distance relay Za
The switch CB1 linked to is opened to protect the electric line below the point A from power failure.

When there is a grounding accident at the point F2 between BDs, the distance relay Zb, which monitors the electric line from the point B to the point D, is located at a position close to the point B.
It operates by detecting the failure of No. 2 and opens the linked switch CB2 to cut the power line from the point B to the point D.

However, at the time of failure of F2, when the switches CB2 and CB3 are not opened and the failure continues, the distance relay Za operates in response to the accident of F2. The switch CB1 is opened. Like this
The operation of directly interrupting the F1 and F2 accidents with the distance relays Za and Zb is called main protection, and the distance relay Zb cannot interrupt the F2 accident with the distance relay Zb which should be the main protection, and the distance relay after a certain time period has elapsed The operation of shutting off with Za is called backup protection.

Further, as shown in FIG. 6, A of one electric line
The fault between B is blocked by monitoring the distance relay Za in one direction from point A to point B, and between the next BC, while monitoring the distance relay Zb from point B to point C, Furthermore, the distance between CDs is monitored by a distance relay Zc, and each section of each electric line is protected while being monitored by a dedicated distance relay.

However, in the distance relay, in order to prevent an error in the transformation ratio of the transformer or the current transformer, an error in the measurement of the relay, or an error in the mutual protection range of the distance relays in the electric line, or a confusion, In the relay Za, the first stage protection range H1 is set with 80% or less between AB as the main protection, and the second stage protection range H2 and the third stage protection range H3 are set stepwise to extend the operating time of the relay. The backup protection function is provided in other sections, and similarly, the distance relays Zb and Zc similarly perform stepwise operation timed coordination by reactance in the protection direction.

Further, in order to operate the distance relay accurately, the left and right blinder elements are provided in the phase characteristic diagram of the distance relay, and the load impedance measured at the time of failure is determined in correspondence with the left and right blinder elements of the phase characteristic diagram.
It is intended to protect the electric line while performing arithmetic processing and preventing malfunction.

[0008]

However, in the distance relay of the tree-type electric line, 80% or less between AB is included in the first-stage protection range H1 as main protection, but the remaining 20% is a backup. As the protection is included in the second protection range H2, the operation time at the time of failure is likely to be delayed, and
If AB between the power supply and the power source is cut off due to a failure, the power failure range is expanded to the following BC and CD, and a wide range of power failure occurs. Also,
For each of the relays Za, Zb, Zc, in order to perform stepwise operation time coordination by one reactance in the protection direction, it is necessary to provide an individual settling value for each distance relay, and maintenance work is complicated. Therefore, the equipment cost will be higher. Further, in the conventional phase characteristic diagram, since the blinder element is not set symmetrically with respect to the resistance axis or the reactance axis, it takes time to input it to the computer and make judgment and arithmetic processing in correspondence with the failure information. Then
There is a problem that the detection capability of the judgment for operating the distance relay is low.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to determine a failure occurring in both directions of an electric line centering on an installation point of a distance relay and to be able to respond promptly. There is no delay in operating time, it is possible to stop the power outage range due to a failure to the minimum range, reduce the facility cost for electric line protection while maintaining the operation time coordination with each distance relay of the same standard, and perform maintenance inspection work. An object of the present invention is to provide a bidirectional protection relay system and a bidirectional protection distance relay in an electric line that can achieve simplification and the like.

[0010]

In order to achieve the above object, the present invention is provided in an electric line 12 and the electric line 12
A distance relay 14 having elements responsive to the resistance value and reactance value measured by introducing the voltage and current of
When a failure occurs at any point of the electric line 12, the positive / negative sign of the reactance value measured by the distance relay 14 is used as a direction determination element for determining the direction of the failure point 16, and the measured reactance value is used in the operation formula. Bidirectional protective relay system 1 in a power line characterized by performing timed coordination of the operation of each distance relay 14 installed in the same power line
It consists of zero.

The distance relay 14 is connected to the electric line 12
When a failure occurs at an arbitrary point on the electric line 12 provided in parallel with each switch 38 in the system, the distance relay 14 arranged at the shortest distance in both directions from the failure point 16 senses the failure and performs the parallel operation. The switch 38 provided may be operated to stop the power failure range within the power line 12 system to the minimum range.

Further, the distance relay 12 is provided with a blinder element determining means 50 for preventing a malfunction due to the measured load impedance, and the blinder element determining means 50 uses the equipment load capacity of the electric line 12 as a reference. Further, the characteristics of the blinder elements 56 and 58 that are effective in both directions may be characterized in that they are symmetrical with respect to the reactance axis 54 and the resistance axis 52 in the resistance-reactance diagram 48, respectively.

Further, the electric line 12 may be configured to be distributed in a loop shape.

Next, the electric line 1 is installed on the electric line 12.
In a distance relay having an element that responds to a resistance value and a reactance value measured by introducing a voltage and a current of 2, when a failure occurs at an arbitrary point of the electric line 12,
A direction determining element that determines the direction of the fault point 16 by the positive / negative sign of the measured reactance value, and an element that uses the measured reactance value in the operation formula to coordinate the operation time limit of each relay installed in the same electric line 12 And a two-way protective distance relay 14 which is characterized in that

The distance relay 14 is connected to the electric line 12
When a failure occurs at an arbitrary point of the electric line 12 installed in parallel in each switch in the system, the distance relay 14 which is arranged at the shortest distance in both directions from the failure point 16 senses the failure and is installed in parallel. The switch 38 may be operated to stop the blackout range within the power line 12 system to a minimum range.

Further, the distance relay 14 is provided with a blinder element determining means 50 for preventing a malfunction due to the measured load impedance, and the blinder element determining means 50 uses the equipment load capacity of the electric line 12 as a reference. Further, the characteristics of the blind elements 56 and 58 that are effective in both directions may be characterized in that they are symmetrical with respect to the reactance axis 54 and the resistance axis 52 in the resistance-reactance diagram 48, respectively.

[0017]

In the bidirectional protection relay system and the bidirectional protection distance relay in the electric line according to the present invention, the bidirectional protection distance relay is installed side by side with each switch installed in the electric line to protect the electric line. To do. The bidirectional protection distance relay can easily determine whether it has occurred on the front side electric line or the rear side electric line centered on the installation point of the distance relay by the positive and negative signs of the reactance value measured at the time of failure occurrence. . While using the measured reactance value in the operation formula, the operation time limit of each distance relay is coordinated to promptly operate the distance relay of the shortest distance near the failure point, and the power failure range in the electric line system is stopped to the minimum range. Therefore, it is possible to promptly confirm the failure point and recover. Also, since each distance relay can protect the electric line while setting the same settling value using the same standard, it is possible to reduce equipment costs for protecting the electric line and simplify maintenance and inspection work. . Further, in the phase characteristic diagram of the distance relay, the blinder element determination means is composed of operation determination straight lines symmetrical to the resistance axis and the reactance axis of the resistance-reactance diagram, and the determination means is easily set in the microcomputer. However, it is possible to promptly process the failure data determination and calculation, and reduce the load required for the calculation processing.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show a bidirectional protective relay system 10 in an electric line according to an embodiment of the present invention. As is clear from the figure, the bidirectional protective relay system 10 in the electric line is installed in the electric line 12 and
A distance relay 14 having an element that responds to a resistance value R and a reactance value X measured by introducing a voltage and a current of 2 is provided, and when the failure 16 occurs at an arbitrary point of the electric line 12, the distance relay 14 Reactance value X measured at
Is used as a direction determination element for determining the direction of the fault point 16, and the measured reactance value X is used in the operation formula to perform the operation timed cooperation of the distance relays 14 installed in the same electric line 12. It is a feature.

The distance relay 14 of the embodiment introduces the voltage V and the current I of the electric line into the inside through the transformer PT and the current transformer CT connected to the electric line 12, and the values of the voltage V and the current I are introduced. The impedance Z from the position where the distance relay 14 is installed to the fault point 16 is measured, and the impedance Z operates at a time proportional to the electrical distance to the fault point 16.

FIG. 4 is a block diagram including a digital type distance relay 14 in which a microcomputer is incorporated. As shown in the figure, the analog voltage and current of the electric line 12 are taken into the input conversion section 18, and the commercial frequency is obtained. Only the component is filtered by the filter 20, and this is input to the analog / digital converter 26 via the sample hold circuit 22 and the multiplexer 24 to be converted into a digital signal.

The converted digital signals of voltage and current are temporarily stored in the data memory 30 from the direct memory access 28, and then the voltage and current data stored in the data memory 30 by the central processing unit 32. To
According to the processing procedure stored in the read-only memory 34, the digital operation processing of the distance relay is performed, and the operation determination circuit 36 transmits the determination signal to the trip coil 40 of the switch 38 to open / close the switch 38.

FIG. 1 shows an electric line 12 implementing a bidirectional protective relay system 10 for an electric line according to the present invention. The electric line 12 has power sources 42, 42 connected to both ends thereof, and further, a resistance value R up to a failure point for each switch 38 provided at each point A, B, C, D, etc. of the electric line 12. ,
Digital type distance relays 14a, 14b, 14c, 14d, 14e that can calculate and determine the reactance value X are provided. The electric line 12 is not limited to the one in which the power source 42 is connected to both ends, and for example, a tree-type electric line in which a distribution line is branched from the main line according to the distribution of load or two tree branches. It includes a loop type electric line or the like in which the type electric line or the like is connected in a loop.

As shown in FIG. 1, the direction determining element for determining the fault point 16 occurring in the electric line 12 corresponds to the electric line 12 and has an arbitrary fault point 16 of the digital type distance relay 14 at each point. 44 is shown. In this operating characteristic diagram 44, the installation points of the distance relays 14 are plotted corresponding to the reactance value X of the electric line between the distance relays 14 installed at each point on the horizontal axis, and the vertical axis thereof is also plotted. On the axis, an operation time period T of the distance relay 14 which operates by detecting a failure occurring at an arbitrary position of the electric line 12 is shown.

When a failure occurs at any position on the electric line 12, the failure is sensed by the impedance Z measured by the distance relay 14 at each point, and the reactance value X of the measured impedance Z is the point A. To determine the operation time period T of each distance relay 14 with respect to the fault point by utilizing the fact that it becomes positive in the forward protection direction from point D to point D and conversely becomes negative in the backward protection direction from point D to point A. , A positive operation line 46a and a negative operation line 46b having a positive and negative slope proportional to the absolute value of the reactance value X are displayed at respective points on the horizontal axis.

Thus, for example, when a ground fault as shown in the figure occurs in the middle of points B and C of the electric line 12, the fault point 16 of the electric line 12 in the operating characteristic diagram 44 is shown.
The operation time period T is automatically selected by the intersection of the perpendicular line from and the positive and negative operation lines 46a and 46b, and the distance relays 14c, 14b, 14d and 14a are set in order from the one near the fault point 16. .

The distance relays 14c and 14b serve as a main protection function for the fault point 16, and the distance relay 14
While d and 14a perform the protection function of the backup equipment, the switches 38 and 38 arranged in parallel with the distance relays 14c and 14b, which are the shortest distance to the fault point 16, are opened, and the power failure range within the 12 lines of the electric line. Can be stopped within the minimum range, and it will be possible to promptly confirm and restore the failure point in the power failure section.

Further, each of the distance relays 14 can protect the electric line 12 in both directions centering on the installation point, can respond promptly when a failure occurs, and can prevent the delay of the operation time T. Further, each of the distance relays 14 is required to emphasize the operation time limit with the operation lines 46a and 46b whose positive and negative slopes are values proportional to the absolute value of the reactance value X.
The distance relays 14 may be of the same standard, and the settling values may be set to the same value, so that the facility cost for protecting the electric line can be reduced, and maintenance and inspection work can be simplified.

Next, in FIG. 2, the two electric lines 12, 12 are connected to the main line on the power source 42 side, and the C of one electric line 12 is connected.
An example is shown in which a switch 38 is connected between D and between GF of the other electric line 12, and the two electric lines 12, 12 are looped around.

Also in this embodiment, when a failure occurs between BCs, the reactance value Xa measured clockwise from the distance relay 14a with respect to the failure point 16 is larger than the reactance value Xb measured from the distance relay 14b. In addition, each distance relay 1 counterclockwise with respect to the failure point 16
Reactance value X measured from 4c, 14e, and 14g
c, Xe, and Xg are Xg>Xe> Xc. Therefore,
The distance relay 14 which is the shortest distance from the failure point 16
b, 14c has a shorter operation time period than other distance relays, and the switches 38, 38 associated with the shortest distance distance relays 14b, 14c are opened to minimize the power failure range in the loop type electric line. Can be stopped.

Also in this loop type electric line, each of the distance relays 14 can protect the electric line 12 in both directions centering on the installation point, can respond promptly when a failure occurs, and delay the operation time T. Therefore, each distance relay 14 can be set to the same settling value by using the same standard, and at the same time, it is possible to reduce the facility cost for protecting the electric line and simplify the maintenance and inspection work.

Next, as shown in the phase characteristic diagram (resistance-reactance diagram) 48 of the distance relay of FIG. 3, each distance relay 14 is provided to prevent malfunction due to the load impedance measured when a failure occurs. A blinder element determination means 50 is provided. The phase characteristic diagram 48 has a resistance axis 52 displaying the resistance component of each impedance on the horizontal axis,
The vertical axis has a reactance axis 54 that displays the reactance component of each impedance.

The blinder element determining means 50 determines the minimum power factor angle of the electric line 12 at the time of failure resistance, arc resistance,
A straight line L1 passing through the origin 0 with a positive and negative blinder power factor angle θ taking into consideration a safety angle affected by the ground resistance or the like as a gradient,
L2, an intersection P1 of the circular line W of the load impedance related to the maximum load current flowing in the electric line 12 with the equipment load capacity of the electric line 12 as a reference, and the straight lines L1 and L2.
It has straight lines L3 and L4 connecting P2 and intersection points P3 and P4.

The straight lines L1, L3, L2 are displayed as a continuous right blinder element 56, and the straight line L
2, L4, L1 are displayed as a continuous left blinder element 58. The load impedance measured by each distance relay 14 at the time of the occurrence of the failure is determined by the right blinder element 56.
Of the right blind region and the left region of the left blinder element 58, the distance relay 14 is set in the inactive region (hatched portion), and the right and left blinder elements 56, 58 are included.
The left-right intermediate area of is set to the operating range of the distance relay 14.

The direction of the positive reactance axis X is the forward protection direction centered on the distance relay, and the direction of the negative reactance axis X is the rear protection direction centered on the distance relay. The fault point 16 can be accurately determined by the sign of the reactance component of
Malfunctions can be prevented. Since the left and right blinder elements 56 and 58 are composed of operation determination straight lines that are symmetrical with respect to the resistance axis 52 and the reactance axis 54 of the phase characteristic diagram (resistance-reactance diagram) 48, the left and right blinder elements 56 and 58. Can be easily set in the microcomputer, and the calculation processing and judgment of the failure data can be processed promptly, and the load required for the calculation processing can be reduced.

As described above, in the bidirectional protective relay system and the bidirectional protective distance relay in the electric line according to the present invention, the distance relay has a bidirectional resistance value and reactance value measuring function from the installation point, In this way, when a failure occurs in the electric line, it is determined whether the direction of the failure point in the electric line is bidirectionally centered on the installation point of the distance relay, and the linked switch is operated promptly. , It is possible to quickly check and restore the faulty part of the electric line while stopping the power outage range to the minimum range.

Further, while coordinating the operation time limits of the distance relays having the same settling value according to the same standard, it is possible to reduce the facility cost for protecting the electric line and simplify the maintenance and inspection work. .

Further, also in the phase characteristic diagram of the distance relay, the blinder elements are arranged in a straight line symmetrical with respect to the resistance axis and the reactance axis, so that the determination of the failure point and the calculation processing can be performed quickly.
The calculation load can be reduced.

[0038]

As described above, according to the bidirectional protective relay system for an electric line according to the first aspect, the resistance which is interposed in the electric line and which is measured by introducing the voltage and current of the electric line. A distance relay having an element that responds to a value and a reactance value, and when a failure occurs at an arbitrary point on the electrical line, the direction determination for determining the direction of the failure point by the positive / negative sign of the reactance value measured by the distance relay As an element, the measured reactance value is used in an operation formula to coordinate the operation time limit of each distance relay installed in the same electric line, thereby making the direction of the fault point in the electric line the distance relay. It is possible to determine which of the two positions is centered around the installation point, and protect the electric line while operating promptly when a failure occurs. In addition, it is possible to reduce the facility cost for protecting the electric line and simplify maintenance and inspection work while coordinating the operation time limits of the distance relays set to the same standard and the same set value.

According to a second aspect of the present invention, the distance relays are arranged in parallel with each switch in the electric line system, and when a failure occurs at any point of the electric line, the distance relay is shortest in both directions. Failure of the electric line due to the fact that the distance relays located in the distance detect the failure and operate the switches installed in parallel to stop the power failure range in the electric line system to the minimum range. The location can be confirmed and restoration can be promptly performed.

According to a third aspect of the present invention, the distance relay is provided with a blinder element determining means for preventing a malfunction due to the measured load impedance, and the blinder element determining means is a facility load of the electric line. The characteristic of the blinder element that is effective in both directions with respect to the capacitance is characterized in that it is symmetrical with respect to the reactance axis and the resistance axis in the resistance-reactance diagram. Can be input to, and the distance relay can quickly determine the fault point in the electric line and the calculation process, and the load required for the calculation can be reduced.

According to claim 4, the electric line is
Since the power is distributed in the form of a loop, the power outage range in the event of a failure can be reduced, and the failure can be checked and recovered quickly.

Next, according to the bidirectional protection distance relay of the fifth aspect, an element which is interposed in the electric line and responds to the resistance value and the reactance value measured by introducing the voltage and current of the electric line. In a distance relay equipped with, when a failure occurs at any point of the electric line, the direction determination element for determining the direction of the failure point by the positive / negative sign of the measured reactance value, and the measured reactance value is used in the operation formula. By arranging the elements that coordinate the operation time limit of each relay installed in the same electric line, the failure point can be promptly judged while monitoring the bidirectional electric line centering on the installation point of the distance relay. Thus, the electric line can be protected, and at the same time, the distance relays of the electric line can cooperate with each other in the operation time limit, and at the same time, the equipment cost for the electric line protection can be reduced and the maintenance and inspection work can be simplified.

According to a sixth aspect of the present invention, the distance relays are arranged in parallel in each switch in the electric line system, and when a failure occurs at any point of the electric line, the distance relay is shortest in both directions. A failure of an electric line is detected by detecting a failure with a distance relay arranged in a distance and operating the switches installed in parallel to stop the power failure range in the electric line system to the minimum range. The location can be confirmed and restoration can be promptly performed.

According to a seventh aspect of the present invention, the distance relay is provided with a blinder element determining means for preventing a malfunction due to the measured load impedance, and the blinder element determining means is a facility load of the electric line. The characteristic of the blind element effective in both directions with respect to the capacity is characterized in that it is symmetrical with respect to the reactance axis and the resistance axis in the resistance-reactance diagram. The point determination and the arithmetic processing can be promptly performed in conjunction with a computer or the like, and the load required for the arithmetic can be reduced.

[Brief description of drawings]

FIG. 1 shows an electric line provided with a bidirectional protective relay system according to the present invention and operating characteristic diagrams of respective distance relays provided on the electric line.

FIG. 2 is an explanatory diagram of a loop type electric line.

FIG. 3 is a phase characteristic diagram of a distance relay according to the present invention including left and right blinder elements.

FIG. 4 is a block diagram of a digital type distance relay incorporating a microcomputer.

FIG. 5 is an explanatory diagram of a tree-type electric line in which a distribution line is branched from a main line according to a distribution of loads.

FIG. 6 is a step-like operation characteristic diagram of each protection relay installed in a conventional electric line.

[Explanation of symbols]

 10 Bidirectional protective relay system in electric line 12 Electric line 14 Distance relay 16 Fault point 38 Switch 44 Operation characteristic diagram 48 Phase characteristic diagram 50 Blinder element determination means 52 Resistance axis 54 Reactance axis 56 Right blind element 58 Left blind element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoru Arita 551 Kawajiri-cho, Kumamoto City Alitech Inc.

Claims (7)

[Claims] 1. A distance relay provided on an electric line, the distance relay having an element that responds to a resistance value and a reactance value measured by introducing a voltage and a current of the electric line, the fault being provided at an arbitrary point on the electric line. When the occurs, the positive / negative sign of the reactance value measured by the distance relay is used as a direction determination element to determine the direction of the fault point, and the measured reactance value is used in the operation formula for each distance installed in the same electric line. A bidirectional protection relay system for electric lines, characterized by performing timed coordination of relays. 2. The distance relay is installed in parallel with each of a plurality of switches in an electric line system, and when a failure occurs at an arbitrary point of the electric line, the distance relay is arranged in the shortest distance in both directions from the failure point. The bidirectional protection in the electric line according to claim 1, wherein a switch provided in parallel is operated by detecting a failure with a distance relay present, and the power failure range in the electric line system is stopped to a minimum range. Relay system. 3. The distance relay includes blinder element determining means for preventing malfunction due to the measured load impedance, and the blinder element determining means uses both of the equipment load capacity of the electric line as a reference. The bidirectional protective relay system for an electric line according to claim 1 or 2, wherein the characteristic of the blinder element that is effective in the opposite direction is symmetrical with respect to the reactance axis and the resistance axis in the resistance-reactance diagram. 4. The bidirectional protective relay system for an electric line according to claim 1, wherein the electric line is distributed in a loop shape. 5. A distance relay, which is provided on an electric line and has an element that responds to a resistance value and a reactance value measured by introducing a voltage and a current of the electric line, wherein a failure occurs at an arbitrary point on the electric line. When a fault occurs, the direction determination element that determines the direction of the fault point by the positive / negative sign of the measured reactance value and the operation time limit coordination of each relay installed in the same electric line by using the measured reactance value in the operation formula. A bidirectional protective distance relay, which is characterized by including: 6. The distance relay is installed in parallel with each switch in an electric line system, and when a failure occurs at any point of the electric line, the distance is set to the shortest distance in both directions from the failure point. The bidirectional protective distance relay according to claim 5, wherein the relay detects a failure and operates the switches arranged in parallel to stop the power failure range in the electric line system to a minimum range. 7. The distance relay includes blinder element determining means for preventing malfunction due to the measured load impedance, and the blinder element determining means uses both as a reference, based on the facility load capacity of the electric line. Bidirectional protective distance relay according to claim 5 or 6, characterized in that the properties of the blind element which are effective in the opposite direction are respectively symmetrical with respect to the reactance axis and the resistance axis in the resistance-reactance diagram.