WO2015078029A1

WO2015078029A1 - Fault locating protection apparatus and method based on power distribution network intelligent terminal

Info

Publication number: WO2015078029A1
Application number: PCT/CN2013/088473
Authority: WO
Inventors: 李国斌; 刘星; 史宏光; 姜睿智; 马仪成; 尹建仑; 张义; 李俊刚; 魏勇
Original assignee: 许继电气股份有限公司; 许昌许继软件技术有限公司; 李国斌; 刘星; 史宏光; 姜睿智; 马仪成; 尹建仑; 张义; 李俊刚; 魏勇
Priority date: 2013-11-29
Filing date: 2013-12-04
Publication date: 2015-06-04
Also published as: CN103683217A; CN103683217B

Abstract

Disclosed are a fault locating protection apparatus and method based on a power distribution network intelligent terminal. The method comprises: dividing a power distribution network into at least one minimum power distribution area, calculating the fault state differential value Ssum of each area, comparing the fault state differential value Ssum of each area with a state set value of this area, determining a differential protection action through short-time delay if the comparison difference of the area satisfies a set condition, and after the differential protection action, tripping off all distribution switches in the area to realize fault isolation. By adopting the fault state differential principle for power distribution areas, the fault locating protection method based on the power distribution network intelligent terminal can control the time for the fault isolation of power distribution networks within 100ms, thereby solving the problems of shortened service life of switches and an impact upon users due to the fact that the switches are opened and closed many times in traditional power distribution network fault isolation and also avoiding an influence caused by the access of a distributed power supply.

Description

TECHNICAL FIELD The present invention relates to the field of relay protection automation in the field of power engineering, and in particular to a fault location protection device and method based on a smart terminal of a distribution network. Background technique

Say

Modern power system consists of power generation, transmission, substation, distribution and users, China's power industry book

For a long time, there have been unhealthy phenomena of "re-issuing, light supply, no use". We have always attached importance to the construction of power generation and transmission facilities. At present, the domestic high-voltage transmission network has been able to accurately locate the fault point, while neglecting the power distribution. The investment and transformation of the system have caused the unfavorable situation of low power supply reliability, poor power quality and large opinions of users. The power distribution link has become a bottleneck problem for the development of China's power companies. The distribution network is the end of the entire power system and is directly oriented to the end users. With the rapid development of the economy, the increase in the power load has placed increasing demands on power supply reliability and power quality. After the distribution network fails, it should be able to locate the fault location in time and accurately, thus quickly isolating the fault area and restoring the power supply in the whole area, minimizing the impact and loss caused by the accident power outage on the social economy and the people's life. In the past, the distribution network was not paid much attention by the state, and the investment was relatively small. The amount of information that can be collected by the distribution line was very small. In the longer period of time, only the recloser and the segmenter could be used to realize the fault area. Automatic isolation and recovery of power. Although this fault location method is simple in structure and relatively high in reliability, it also has the following serious drawbacks:

1) It takes a long time to cut off the fault, which often takes several minutes or even longer; 2) The non-fault interval switch operates frequently, shortening the switch life; 3) Multiple short-circuit current surges, multiple power failures, The user has serious impact; 4) When the ring network is used, the non-fault part is completely de-energized once, and the scope of the accident is expanded; 5) With the access of the distributed power source, the distribution network is changed from the original single-supply network to the complex multi-power supply. Powered active networks, based on traditional fault location methods, become more difficult or even completely ineffective. Summary of the invention

The object of the present invention is to provide a fault location protection method based on a smart terminal of a distribution network, to solve the problem that the existing fault location method has a long cut-off time and a large influence range, and at the same time provides a position protection device using the method.

In order to achieve the above object, the technical solution adopted by the present invention is: A fault location protection method based on a smart terminal of a distribution network, comprising the following steps:

(1) dividing the distribution network into at least one minimum power distribution area, and each terminal in each area corresponds to one power distribution switch;

(2) Calculating the fault state differential value of each region Ssum, Ssum is related to the fault state value of each terminal in the corresponding region, and the fault state value reflects the overcurrent information and flow direction information of the corresponding terminal to the fault current;

(3) Compare the fault state differential value Ssum of each zone with the state set value of the zone. If the difference of the corresponding zone meets the set condition, the differential protection action is confirmed by a short delay. After the protection action, all the distribution switches in the area are tripped to achieve fault isolation.

The setting condition in the step (3) shown is that the fault state differential value is greater than or equal to the state set value. In step (2), the fault state differential value Ssum is calculated as: Ssum = | S1 -S2 -... - Sn | , where S1 is the fault state value closest to the system power supply side terminal, /2 is the region Number of internal terminals, Sn is the fault status value of the nth terminal; 2 is 0 if there is no overcurrent in the terminal; 1 is if overcurrent and the direction is the same as the positive direction; if overcurrent and the direction is opposite to the positive direction Time? is -1; The positive direction is defined as the direction of current flow from the system power supply side to the load side.

The state setting value is a value of the number of distributed power sources input in the area plus one, and each area counts the number of all distributed distributed power sources in the downstream direction when setting the state setting value of the area. The downstream direction is set to the direction from the system power supply side to the load side.

The terminal can automatically correct the state setting value according to the dispatching and retracting condition of the distributed power source. If the switch corresponding to the distributed power source is in the exit state, the state setting value is automatically decremented by one.

When collecting the fault status value of the terminal, each terminal transmits the overcurrent and direction information to its integrated 0NU module in GOOSE mode, and then uploads it to the EP0N network by the ONU module, and then the fault status value of the terminal is GOOSE through the EP0N network. The mode is sent to other terminals in the area, and the fault status information of other terminals in the area is received at the same time.

The technical solution adopted by the present invention is: A fault location protection device based on a smart terminal of a distribution network, comprising:

Dividing the distribution network into modules of at least one minimum distribution area; each terminal in each area corresponds to one distribution switch;

The module for calculating the fault state differential value Ssum of each region, Ssum is related to the fault state value of each terminal in the corresponding region, and the fault state value reflects the overcurrent information and flow direction information of the corresponding terminal to the fault current;

It is used to compare the fault state differential value Ssum of each region with the state set value of the region, and if the difference after the corresponding region meets the set condition, the differential protection action is confirmed by a short delay, and the differential After the protection action, all the power distribution switches in the area are tripped to realize the fault isolation module.

The fault state differential value Ssum is calculated as: Ssum = | S1 - S2 -... - Sn |, where S 1 is the fault state value closest to the system power supply side terminal, and is the station of the terminal in the area Number, Sn is the fault status value of the nth terminal; if the terminal has no overcurrent, 2 is 0; if the current is overcurrent and the direction is the same as the positive direction, it is 1; if the current is overcurrent and the direction is opposite to the positive direction? -1 ; The positive direction is defined as the direction of current flowing from the system power supply side to the load side.

The state setting value is a value of the number of distributed power sources input in the area plus one, and each area counts the number of all distributed distributed power sources in the downstream direction when setting the state setting value of the area. The downstream direction is set to a direction from the system power supply side to the load side; the setting condition is that the fault state differential value is greater than or equal to the state set value.

The invention is based on a fault location protection device and method for a smart terminal of a distribution network, and is an intelligent feeder automatic fault location method coordinated by all intelligent terminal devices (RTU or FTU) in a minimum power distribution area, adopting a power distribution area fault state The differential principle compares the fault state differential value with the state set value. If the difference after the corresponding region meets the set condition, the differential protection action is confirmed by a short delay, and the differential protection action is skipped. All distribution switches in the area are fault isolated. The method can control the fault isolation time of the distribution network within 100ms, avoiding the shortening of the switch life caused by the multiple times of the traditional distribution network fault isolation switch and the impact on the user, and is not affected by the distributed power access. .

The terminal adopts IEC61850 modeling, and can send and receive status information in G00SE mode. At the same time, EP0N technology is adopted in network transmission, which has obvious advantages.

DRAWINGS Figure 1 is a schematic diagram of the wiring of the distribution network;

Figure 2 is a GOOSE communication network diagram;

Figure 3 is a schematic diagram of the expansion of the power distribution area;

Figure 4 is a schematic diagram of an incomplete power distribution area.

detailed description

The present invention will be further described below in conjunction with the drawings and specific embodiments.

In a power distribution system, a closed collection of distribution switches and feeder segments is referred to as a distribution area. If all the endpoints of an area are switches and there are no internal points or all internal points are T contacts, the area is called the minimum distribution area, and the distribution switch directly connected to the load becomes the distribution terminal. The distribution network consists of multiple minimum distribution areas and multiple distribution ends. Distribution network fault location is equivalent to addressing the minimum power distribution area and distribution terminal fault location.

The current direction is defined as the positive direction from the system side to the load side, that is, the current flows from the upstream direction to the downstream direction. For a multiple power system, select one of the power supplies as the system power supply, and the other power supplies are considered as distributed power sources when defining the current direction.

The invention is based on a fault location protection method for a smart terminal of a distribution network, and includes the following steps:

(1) dividing the distribution network into at least one minimum power distribution area, and each terminal is provided with a power distribution switch;

(2) Calculate the fault state differential value Ssum of each area. Ssum is related to the fault status value of each terminal in the corresponding area. The fault status value reflects the overcurrent information and flow direction information of the fault current of the terminal.

(3) Compare the fault state differential value Ssum of each region with the state set value of the region, and if the difference after the corresponding region meets the set condition, the differential protection action is confirmed by a short delay, and the difference is After the protection action, all the distribution switches in the area are tripped to achieve fault isolation.

For the power distribution switch located at the end of the distribution network, when an overcurrent is detected (ie, the overcurrent component is activated), the switch is turned off by a short delay. This action protection is a conventional technique in the art, and will not be described herein.

In this embodiment, the setting condition is that the fault state differential value is greater than or equal to the state set value. The status setting value is set according to the number of distributed power supplies in the distribution network section: If the number of distributed power supplies is n, the setting value should be set to n+l. When setting the status setting value of this area, each area counts the number of all distributed distributed power supplies in the downstream direction, and the downstream direction is set from the system power supply side to the load side. That is, if there is a newly-input distributed power supply in a certain distribution area, all the areas upstream of the area should also be counted in the set state setting value, and the downstream area of the area is Excluding the distributed power supply. The terminal can automatically correct the state setting value according to the dispatching and retracting condition of the distributed power source. If the switch corresponding to the distributed power source is in the exit state (jumping and no flow), the state setting value is automatically decremented by one.

The invention also provides a positioning protection device using the above method, comprising:

A module for calculating a fault state differential value Ssum of each region, Ssum is related to a fault state value of each terminal in the corresponding region, and the fault state value reflects an overcurrent of the fault current of the corresponding terminal Information and flow direction information;

As shown in FIG. 2, each intelligent terminal is modeled according to IEC61850. When collecting the fault state value of the terminal (the fault state information includes overcurrent information and current direction information), the overcurrent component and the current component are performed in real time according to the collected current and voltage analog quantity. The directional component discriminates and transmits the status information to its integrated 0NU module in GOOSE mode, and then uploads it to the EP0N network by the ONU module, and simultaneously receives the GOOSE status information of other terminals in the area. The terminal performs fault state value calculation and logic judgment according to its own and received GOOSE state information, and finally completes fault location and protection actions.

When overcurrent and direction discrimination are made: The terminal sets the overcurrent start setting value, and sets the overcurrent action when the collected current amount is greater than the starting set value; the directional component action criterion is as follows: 45. ≥ _arg ^≥-l05.

The invention will now be described in terms of specific application examples.

As shown in the distribution network shown in Figure 1, the current direction is defined as " >". According to the definition of the minimum distribution area, it can be divided into 5 distribution areas and 6 distribution terminals.

The following table shows the related switches of the five distribution areas:

The six distribution terminals are

Define the current direction as "one:

Distribution area and 6 distribution terminals.

The following table shows the related switches of the five distribution areas:

The six distribution terminals are: FTU21, 22, 23, 24, 31, 5.

Taking the distribution area 1 as an example, the associated switches are FTU1, 2, 21, 22. Then FTU1 will receive the GOOSE status information of FTU2, 21, 22; FTU2 will receive FTU1, 21, 22; FTU21 will receive FTU1, 2, 22; FTU22 will receive FTU1, 2, 21.

As shown in Figure 3, the power distribution area is expanded. For an important segment switch on the distribution network, if the differential protection action switch fails (the mechanism is stuck, etc.), in order to prevent the scope of the fault from expanding, the minimum distribution can be The electrical area is expanded to form an extended range of differential protection. As shown in Figure 3, after the FTU2 switch fails, the original minimum power distribution area is expanded. The expanded minimum power distribution area associated switch includes: FTU1, 3, 21, 22, 23.

Figure 4 shows a schematic diagram of an incomplete power distribution section. Under normal conditions, the associated switch of zone 1 includes FTU1, 2, 21, 22. Since there is no power supply on the FTU21 and 22 sides, the fault status value is always 0, so the power distribution section can be simplified as shown in the figure, resulting in incomplete power distribution section and incomplete fault state differential.

The accuracy of the fault location of the method is verified by taking the failure of the area 3 as an example. When the area 3 fails, the fault status values of each terminal in the distribution network and the fault status values of each area are as follows:

Terminal fault status value

Differential status and operating status of each area

From the above table, it can be determined that it is a zone 3 fault, and the accuracy of the fault location of the method is verified.

Claims

claims

1. A fault location protection method based on intelligent terminals of distribution network, which is characterized by including the following steps:

(1) Divide the distribution network into at least one minimum distribution area, and each terminal in each area corresponds to a distribution switch;

(2) Calculate the fault status differential value Ssum of each area. Ssum is related to the fault status value of each terminal in the corresponding area. The fault status value reflects the overcurrent information and flow direction information of the corresponding terminal to the fault current;

(3) Compare the fault state differential value Ssum of each area with the state setting value of the area. If the difference after comparison in the corresponding area meets the set conditions, the differential protection action will be confirmed after a short delay. The difference After the automatic protection action, all distribution switches in the area are tripped to achieve fault isolation.

2. The fault location protection method based on intelligent terminals of the distribution network according to claim 1, characterized in that: the setting condition in step (3) shown is that the fault state differential value is greater than or equal to the state setting value.

3. The fault location protection method based on intelligent terminals of the distribution network according to claim 1, characterized in that: the calculation formula of the fault state differential value Ssum in step (2) is: Ssum = | S1 - S2 - ... - Sn I , where S1 is the fault status value closest to the terminal on the power supply side of the system, n is the number of terminals in the area, Sn is the fault status value of the nth terminal; 2 is 0 if there is no overcurrent in the terminal ; If there is overcurrent and the direction is the same as the positive direction, it is 1; If there is overcurrent and the direction is opposite to the positive direction, it is - 1; The positive direction is defined as the direction of current flowing from the power supply side to the load side of the system.

4. The fault location protection method based on intelligent terminals of the distribution network according to claim 2 or 3, characterized in that: the state setting value is added to the number of distributed power sources invested in the area by 1, and every When setting the status setting value of each area, the number of all distributed power sources input in the downstream direction is taken into account. The downstream direction is set as the direction from the system power supply side to the load side.

5. The fault location protection method based on intelligent terminals of the distribution network according to claim 4, characterized in that: the terminal can automatically correct the status setting value according to the switching status of the distributed power supply. If the switch corresponding to the distributed power supply In the exit state, the status setting value automatically decreases by 1.

6. The fault location protection method based on intelligent terminals of the distribution network according to claim 1, characterized in that: when collecting the fault status value of the terminal, each terminal transmits the overcurrent and direction information to its own integrated system in GOOSE mode. 0NU module, and then the 0NU module uploads it to the EP0N network, and then sends the fault status value of this terminal to other terminals in the area in GOOSE mode through the EP0N network, and at the same time receives the fault status information of other terminals in the area.

7. A fault location protection device based on intelligent terminals of the distribution network, characterized by including: a module that divides the distribution network into at least one minimum distribution area; each terminal in each area corresponds to a distribution switch;

A module used to calculate the fault status differential value Ssum of each area. Ssum is related to the fault status value of each terminal in the corresponding area. The fault status value reflects the overcurrent information and flow direction information of the corresponding terminal to the fault current;

It is used to compare the fault state differential value Ssum of each area with the state setting value of the area. If the difference after comparison in the corresponding area meets the set conditions, the differential protection action will be confirmed after a short delay. After the protection action, all distribution switches in the area are tripped to achieve fault isolation.

8. The fault location protection device based on the intelligent terminal of the distribution network according to claim 7, characterized in that: the calculation formula of the fault state differential value Ssum is: Ssum = I SI - S2 - ... - Sn I, where, S1 is the fault state value closest to the terminal on the power supply side of the system, /2 is the terminal in the area. The number of terminals, Sn is the fault status value of the nth terminal; if there is no overcurrent in the terminal, 2 is 0; if there is overcurrent and the direction is the same as the positive direction, ? is 1; if there is overcurrent and the direction is opposite to the positive direction, ? is -1; the positive direction is defined as the direction of current flowing from the power supply side to the load side of the system.

9. The fault location protection device based on the intelligent terminal of the distribution network according to claim 7 or 8, characterized in that: the state setting value is the number of distributed power sources invested in the area plus 1, and each When setting the status setting value of the area, the number of distributed power sources put in in the downstream direction is taken into account. The downstream direction is set as the direction from the system power supply side to the load side; the setting condition is The differential value in fault state is greater than or equal to the state setting value.

10. The fault location protection device based on intelligent terminals of the distribution network according to claim 7, characterized in that: when collecting the fault status value of the terminal, each terminal transmits the overcurrent and direction information to its own integrated system in GOOSE mode. 0NU module, and then the 0NU module uploads it to the EP0N network, and then sends the fault status value of this terminal to other terminals in the area in GOOSE mode through the EP0N network, and at the same time receives the fault status information of other terminals in the area.