CN116417968B - Low-voltage relay protection method based on low-code controller - Google Patents

Abstract

The invention discloses a low-voltage relay protection method based on a low-code controller, which belongs to the field of relay protection, adopts an AOE network to model a low-voltage relay protection strategy, judges an occurrence event in an AOE node by utilizing collected current quantity, and executes a required action in an AOE side, thereby realizing three protection strategies of instantaneous current quick-break protection, time-limited current quick-break protection and overload protection; the invention provides a low-voltage relay protection method based on a low-code controller, which carries out visual modeling on a low-voltage relay protection strategy through an AOE network, flexibly realizes the low-voltage relay protection strategy in the low-code controller through an AOE network configuration mode, can obviously reduce the development and application thresholds of the low-voltage relay protection, and can realize the low-voltage relay protection in one terminal device.

Description

A low-voltage relay protection method based on low-code controller

technical field

The invention relates to the technical field of relay protection, in particular to a low-voltage relay protection method based on a low-code controller.

Background technique

Under the background of the implementation of dual carbon targets and new power system construction, the scale and capacity of distributed power sources such as solar panels, wind power generation, electric vehicles, fuel cells, and large-scale power generation and power supply modules on the user side have developed rapidly, and will become the energy industry in the future. It is one of the important means to effectively reduce energy consumption, save investment, and improve the reliability and flexibility of low-voltage power grid energy deployment. However, distributed power sources are connected to the low-voltage power grid one after another, and upgrading the traditional low-voltage power grid structure to a multi-terminal active network structure will bring complex changes to the operation mode of the low-voltage power grid, making the traditional low-voltage power grid relay protection configuration scheme no longer applicable .

At present, the widely used relay protection devices need to be written in advance by the manufacturer, and the relay protection function is realized through simple logical judgment. The update and maintenance of the relay protection strategy requires a large amount of work, and it is difficult to adapt to the new environment. The need for flexible configuration of low-voltage relay protection strategies under the background of massive energy access. At the same time, the current microcomputer protection devices are expensive, which limits the wide application of low-voltage station area protection and the development of distribution feeder automation. How to enable electrical engineering professionals with non-programming technical background to independently realize the flexible and easy configuration of low-voltage relay protection strategies, and at the same time reduce the cost of low-voltage relay protection devices, is the current technical problem and blocking point in the development of low-voltage relay protection .

Activity On Edge (AOE) network is a weighted directed graph in which vertices represent events and directed edges represent activities, where the weight on the edges represents the duration of the activity. AOE is often used to describe and analyze the planning and implementation process of a project. Considering that the control process usually responds to certain states of the controlled object (which can be defined as events), it can also be better described using the AOE network. The low-code controller uses the AOE network to model the control process. During application, the control strategy can be transformed into an AOE network for configuration to realize the control function.

Contents of the invention

The purpose of the present invention is to provide a low-voltage relay protection method based on a low-code controller to solve the problems raised in the above-mentioned background technology.

To achieve the above object, the present invention provides the following technical solutions:

A low-voltage relay protection method based on a low-code controller, comprising the following steps:

Step 1. Use the AOE network to model the low-voltage relay protection strategy, use the collected current to judge the occurrence of events in the AOE node, and execute the required actions in the AOE edge;

Step 2. The low-code controller executes the control strategy according to the AOE network, supports the configuration of the control strategy in the form of the AOE network, and configures the model obtained by modeling the AOE network described in step 1 into the low-code controller to realize the low-voltage relay protection strategy .

As a further technical solution of the present invention: Step 1 specifically includes: 101) The relay protection strategy determines whether a fault occurs and issues a switch trip instruction by logically judging the signals collected by the power system. This process adopts AOE network modeling, low-voltage Relay protection adopts current protection, that is, judges whether a fault occurs through the collected current, and establishes an AOE network with a low-voltage relay protection strategy; 102) Connect nodes through directed edges in the AOE network, and perform specific actions in the edges .

As a further technical solution of the present invention: the AOE network has three stages of protection: instantaneous current quick-break protection, time-limited current quick-break protection and overload protection, wherein the instantaneous current quick-break protection and time-limited current quick-break protection are the main protection, and the overload protection is the backup Protect.

As a further technical solution of the present invention: the AOE network includes the following nodes:

Node 1: The starting node of the AOE network. After each update of the measured current value, judge whether there is an overload by comparing the measured current value with the set overload protection current value. If so, start the AOE network and execute side 1; 2. The actions of side 1;3 and side 1;4, where side 1;2 means the side connecting node 1 and node 2, and the rest are analogized;

Node 2: Judging whether the measured current value is greater than the instantaneous current quick-break protection setting value, if so, judging that a fault has occurred, and performing the actions of side 2; 6;

Node 3: Judging whether the measured current value is greater than the time-limited current quick-break protection value, if so, it needs to go through the delay time set by the time-limited current quick-break protection, and then judge whether the current value of the measuring point is greater than the time-limited current quick-break protection value, and execute side 3; 5 actions;

Node 4: After the delay time set by the overload protection, judge again whether the measured current value is greater than the overload protection current setting value, if so, judge that a fault has occurred, and execute the actions of sides 4; 6;

Node 5: After the delay time set by the time-limited current quick-break protection, judge again whether the current value of the measuring point is greater than the set value of the time-limited current quick-break protection.

Node 6: AOE network end node;

The actions of the AOE side in the AOE network are as follows:

Side 1; 2: enter node 2, and further judge whether the measured current value is greater than the instantaneous current quick-break protection setting value;

Side 2; 6: Send the switch trip command, and record that this is a section of protection exit and enter the end node;

Side 1; 3: Enter node 3, and further judge whether the measured current value is greater than the time-limited current quick-break protection setting value;

Side 3; 5: Record the current time, enter node 5, and judge again after the delay time set by the time-limited current quick-break protection in node 5 whether the measured current value is greater than the set value of the time-limited current quick-break protection;

Side 5; 6: Send the switch trip command, and record that it is the second-stage protection exit at this time, and enter the end node;

Side 1; 4: Record the current time, enter node 4, and judge whether the measured current value is greater than the overload protection current setting value again after the delay time set by the overload protection in node 4;

Side 4; 6: Send the switch trip command, and record that it is the exit of the three-stage protection at this time, and enter the end node.

As a further technical solution of the present invention: in step 2, modify the three-stage protection fixed value in the AOE network, and the delay time of time-limited current quick-break protection and overload protection, and the protection strategy configuration can be updated to adapt to the new energy in the low-voltage power system Volatility-induced protection adjustments are required.

Compared with prior art, the beneficial effect of the present invention is:

The present invention proposes a low-voltage relay protection method based on a low-code controller. The low-voltage relay protection strategy is intuitively modeled through the AOE network, and the low-voltage relay protection is flexibly realized through the AOE network configuration mode in the low-code controller. The strategy can significantly reduce the development and application threshold of low-voltage relay protection, and at the same time, low-voltage relay protection can be realized in one terminal device, which can effectively reduce the construction cost of low-voltage relay protection and help the development of distribution feeder automation.

Description of drawings

Fig. 1 is an AOE network diagram of the middle and low voltage relay protection strategy of the present invention.

Fig. 2 is a simulation model diagram of a short-circuit fault in a low-voltage power system according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of the first result of the simulation test of the low-voltage relay protection strategy in the embodiment of the present invention.

Fig. 4 is a schematic diagram of the second result of the simulation test of the low-voltage relay protection strategy in the embodiment of the present invention.

Fig. 5 is a schematic diagram of the third result of the simulation test of the low-voltage relay protection strategy in the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1-Figure 5, a low-voltage relay protection method based on a low-code controller, the method includes the following steps:

1) Use the AOE network to model the low-voltage relay protection strategy, use the collected current to judge the occurrence of events in the AOE node, and perform the required actions in the AOE edge. The specific steps are as follows:

101) The relay protection strategy makes logical judgments on the signals collected by the power system to determine whether a fault occurs and issue a switch trip command. This process is very suitable for AOE network modeling. Low-voltage relay protection usually adopts current protection, that is, judges whether a fault occurs through the collected current. The AOE network that establishes the low-voltage relay protection strategy is shown in Figure 1. The AOE network realizes three-stage protection: instantaneous current quick-break protection, time-limited current quick-break protection and overload protection. Among them, the instantaneous current quick-break protection and the time-limited current quick-break protection are the main protections, and the overload protection is the backup protection. The definition of each AOE node in Fig. 1 is as follows.

Node 1: The starting node of the AOE network. After each measured current value is updated, by comparing the measured current value with the set overload protection current value, it is judged whether there is an overload, if so, start the AOE network, and execute side 1;2, side 1;3, side 1; 4 actions.

Node 2: Judging whether the measured current value is greater than the instantaneous current quick-break protection setting value, if so, judging that a fault has occurred, and performing the actions of side 2; 6.

Node 3: Judging whether the measured current value is greater than the time-limited current quick-break protection value, if so, it needs to go through the delay time set by the time-limited current quick-break protection, and then judge whether the current value of the measuring point is greater than the time-limited current quick-break protection value, and execute side 3; 5 actions.

Node 4: After the delay time set by the overload protection, judge again whether the measured current value is greater than the overload protection current setting value, if so, judge that a fault has occurred, and execute the actions of sides 4; 6.

Node 5: After the delay time set by the time-limited current quick-break protection, judge again whether the current value of the measuring point is greater than the set value of the time-limited current quick-break protection.

Node 6: AOE network end node.

102) In the AOE network, nodes are connected through directed edges, and specific actions are performed in the edges. The actions of each AOE edge in Figure 1 are defined as follows:

Side 1; 2: Enter node 2, and further judge whether the measured current value is greater than the instantaneous current quick-break protection setting value.

Side 2; 6: Send the switch trip command, and record that this is a section of protection exit and enter the end node.

Side 1; 3: Enter node 3, and further judge whether the measured current value is greater than the time-limited current quick-break protection setting value.

Side 3; 5: Record the current time, enter node 5, and judge whether the measured current value is greater than the set value of the time-limited current quick-break protection after the delay time set by the time-limited current quick-break protection in node 5.

Side 5; 6: Send the switch trip command, and record that this is the second-stage protection exit and enter the end node.

Side 1; 4: Record the current time, enter node 4, and judge whether the measured current value is greater than the overload protection current setting value again after the delay time set by the overload protection in node 4.

Side 4; 6: Send the switch trip command, and record that it is the exit of the three-stage protection at this time, and enter the end node.

The low-code controller supports the configuration of control strategies in the form of AOE network, and the model obtained by modeling the AOE network described in step 1) is configured into the low-code controller to realize the low-voltage relay protection strategy. The protection strategy configuration can be updated by modifying the three-stage protection settings in the AOE network, as well as the delay time of the time-limited current quick-break protection and overload protection.

Experimental example:

The short-circuit fault simulation model of the low-voltage power system shown in Figure 2 is built to verify the effectiveness of the proposed implementation method of the low-voltage relay protection strategy based on the low-code controller. In Figure 2, S is the power node, Zs is the output impedance of the power node, Breaker is the switch, Load1 and Load2 are the loads, Iabc and Vabc are the ammeter and voltmeter respectively, and Line1 and Line2 are the distribution lines. comm is an S-function module, which realizes communication with the low-code controller, sends the measured maximum value of the three-phase current of the line and time signals to the low-code controller, and receives the control instructions of the low-code controller to control the switch. Fault1, Fault2 and Fault3 modules are line-to-ground short-circuit fault simulation modules, where Fault1 module is placed within the protection range of the first section of the line, Fault2 module is placed outside the protection range of the first section and within the protection range of the second section, and Fault3 is placed outside the protection range of the second section and third section. within the range of protection.

A short-circuit fault is set within the protection range of a section of the line. The current on the line obtained by simulation is shown in Figure 3. The simulation model receives the switch trip command 0.02s after the fault occurs, and the fault has been removed 0.024s after the fault.

Set a short-circuit fault outside the protection range of the first stage of the line and within the protection range of the second stage. The current on the line obtained by simulation is shown in Figure 4. The simulation model received the switch trip command 0.08s after the fault occurred, and it was cut off at 0.084s after the fault Fault.

A short-circuit fault is set outside the protection range of the second section of the line and within the protection range of the third section. The current on the line obtained by simulation is shown in Figure 5. The simulation model receives the switch trip instruction 1.02s after the fault occurs, and the fault is completed 1.024s after the fault. Remove fault.

Based on the above analysis results, it can be seen that the implementation method of the low-voltage relay protection strategy based on the low-code controller can reliably and selectively remove faults, which verifies the effectiveness of the method. The invention adopts the AOE network to model the low-voltage relay protection strategy intuitively, and realizes the low-voltage relay protection strategy flexibly through the AOE network configuration mode in the low-code controller, which can significantly reduce the development and application threshold of the low-voltage relay protection, and at the same time The low-voltage relay protection is implemented in a terminal device, which can significantly reduce the construction and application cost of low-voltage relay protection compared with the use of microcomputer protection devices.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only includes an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (1)

1. The low-voltage relay protection method based on the low-code controller is characterized by comprising the following steps of:

step 1, modeling a low-voltage relay protection strategy by adopting an AOE network, judging an event in an AOE node by utilizing the collected current amount, and executing a required action in an AOE edge, wherein the step 1 specifically comprises the following steps: 101 The relay protection strategy determines whether a fault occurs or not and issues a switch tripping instruction by logically judging signals collected by the power system, the process adopts AOE network modeling, the low-voltage relay protection adopts current protection, namely whether the fault occurs or not is judged by the collected current amount, and an AOE network of the low-voltage relay protection strategy is established; 102 Connecting nodes by directed edges in an AOE network, and performing specific actions in the edges, the AOE network having three segments of protection: instantaneous current quick-break protection, time-limited current quick-break protection and overload protection, wherein the instantaneous current quick-break protection and the time-limited current quick-break protection are main protection, and the overload protection is backup protection;

the AOE network includes the following nodes:

node 1: after each time of updating of the measured current value, the initial node of the AOE network judges whether overload occurs or not by comparing the measured current value with the set overload protection current constant value, if so, the initial node of the AOE network is started to execute actions of sides 1, 2, 1, 3 and 1, 4;

node 2: judging whether the measured current value is larger than the instantaneous current quick-break protection fixed value, if so, judging that a fault occurs, and executing the actions of the sides 2 and 6;

node 3: judging whether the measured current value is larger than a time-limited current quick-break protection fixed value, if so, needing to pass the time delay time set by the time-limited current quick-break protection, judging whether the measured point current value is larger than the time-limited current quick-break protection fixed value again, and executing the actions of the edges 3 and 5;

node 4: after the delay time set by overload protection, judging whether the measured current value is larger than the overload protection current fixed value again, if so, judging that the fault occurs, and executing the actions of the edges 4 and 6;

node 5: after the time delay time set by the time-limited current quick-break protection is passed, judging whether the current value of the measuring point is larger than the fixed value of the time-limited current quick-break protection again, if so, judging that a fault occurs, and executing the actions of the edges 5 and 6;

node 6: an AOE network end node;

the actions of the AOE edge in the AOE network are as follows:

edge 1;2: entering a node 2, and further judging whether the measured current value is larger than an instantaneous current quick-break protection fixed value;

edge 2;6: a switch tripping instruction is sent, a section of protection outlet is recorded at the moment, and the protection outlet enters an ending node;

edge 1;3: entering a node 3, and further judging whether the measured current value is larger than a time-limited current quick-break protection fixed value;

edge 3, 5: recording the current time, entering a node 5, and judging whether the measured current value is larger than a time-limited current quick-break protection fixed value again after the time delay time set by the time-limited current quick-break protection in the node 5;

edge 5;6: a switch tripping instruction is sent, a two-section protection outlet is recorded at the moment, and the switch tripping instruction enters an ending node;

edge 1;4: recording the current time, entering a node 4, and judging whether the measured current value is larger than the overload protection current fixed value again after the delay time set by overload protection in the node 4;

edge 4;6: a switch tripping instruction is sent, a three-section protection outlet is recorded at the moment, and an ending node is entered;

step 2, the low-code controller executes a control strategy according to the AOE network, supports configuration of the control strategy in the form of the AOE network, and configures the model obtained by the AOE network modeling in the step 1 into the low-code controller to realize the low-voltage relay protection strategy; the three-section protection fixed value in the AOE network and the delay time of the limited current quick-break protection and overload protection are modified, so that the protection strategy configuration can be updated, and the protection adjustment requirement caused by new energy fluctuation in the voltage power system is met.