Distribution network distributed resource regulation and control strategy

Abstract

A power distribution network distributed resource regulation and control strategy is suitable for formulating a regulation and control scheme of low-voltage distributed resources in a power distribution network, adopts a hierarchical regulation and control principle, and takes whether abnormal conditions such as forward and reverse heavy overload and voltage bidirectional out-of-limit occur in a medium-voltage line of the power distribution network as a research and judgment basis. The original operation mode of the line is preferentially adjusted to restore the normal operation of the distribution network, if the regulation and control requirement cannot be met, medium-voltage distributed resources are regulated and controlled to restore the normal load rate of the line, and if the regulation and control requirement still cannot be met, low-voltage distributed resource group regulation is carried out until the load rate of the line completely returns to normal. According to the invention, three different levels of regulation and control strategies are realized through three different research and judgment logics, and the optimal regulation and control scheme of the low-voltage distributed resources in the power distribution network in different scenes is realized; the blank of blind adjustment of existing distributed resource regulation and control is improved, the distribution network distributed resource regulation and control efficiency is improved, the negative influence of distributed energy on the power distribution network is reduced, and the absorption capacity of the distributed energy is improved.

Description

Technical Field

[0001] The present invention belongs to the field of electrical engineering, and in particular is a distributed resource control strategy for a distribution network. Background Art

[0002] With the continuous advancement of "dual carbon" development and energy transformation, the traditional power system is evolving towards a new power system that is clean, low-carbon, safe, controllable, flexible, efficient, intelligent and friendly. The core characteristics of the new power system are the widespread access of a high proportion of new energy, the dominant position of new energy, the accelerated replacement of fossil energy, and becoming the main form of energy; it is also reflected in the flexible and reliable allocation of resources by the highly elastic power grid, and the compatibility of new energy power generation with greater randomness, volatility, and fragility.

[0003] Due to the influence of early power infrastructure factors, the north and south power grids in my country have different degrees of adaptability to the consumption of connected industrial and commercial distributed photovoltaic systems. At present, there is a lack of effective carrying capacity assessment, real-time monitoring and regulation and control methods for distributed photovoltaics. The regulation of distributed resources is still in the "blind adjustment" stage, which has a certain impact on the load forecast and power balance of the power grid. Furthermore, the distribution network load does not match the installed capacity of new energy. With the large-scale access of high-penetration distributed photovoltaics, the photovoltaic power generation in some low-voltage areas will exceed the consumption capacity of users in the area, resulting in the problem of reverse overload and terminal overvoltage in the local power grid.

[0004] Therefore, how to coordinate and control distributed resources, reduce the negative impact of distributed renewable energy on distribution networks, and improve the ability to absorb renewable energy is of great research significance. Summary of the invention

[0005] In view of the current technical defects or improvement needs of distributed resource regulation, the present invention aims to provide a distributed resource regulation strategy for distribution network, which aims to reduce the negative impact of distributed energy on distribution network and improve the distributed energy absorption capacity.

[0006] In order to achieve the above object, a distributed resource control strategy for a power distribution network of the present invention comprises the following steps:

[0007] Step 1: The distribution terminal monitors the operating status of the medium voltage distribution network, taking the occurrence of forward and reverse heavy overload or voltage exceeding the limit as the boundary, and uploads an alarm signal when abnormal data is monitored;

[0008] Step 2: After receiving the alarm information, the master station of the distribution automation system starts to generate and issue distributed resource control strategies in three levels;

[0009] Step 3: The first level is that the master station of the distribution automation system adjusts the operation mode of the medium voltage distribution network, generates a line operation adjustment plan according to the medium voltage line connection status and overload, and if the operation section returns to normal after the operation mode adjustment, returns to step 1; if there are no remaining transferable feeders or the line operation section is still abnormal after the line operation mode adjustment, execute step 4;

[0010] Step 4: The second level is that the master station of the distribution automation system regulates the medium voltage distributed resources. If the operation section returns to normal after the medium voltage distributed resources are regulated, return to step 1; if the line operation section is still abnormal after regulation, execute step 5;

[0011] Step 5: The third level is that the distribution automation master station sends the control strategy to the intelligent fusion terminal edge device in the substation based on the access status of low-voltage distributed resources within the range, and regulates the low-voltage distributed resources. After the regulation is completed, it returns to step 1.

[0012] In step 1 of the present invention, the medium voltage section data is continuously monitored through the power distribution terminal, and when an abnormal situation occurs in which the line is heavily overloaded in the forward and reverse directions or the voltage exceeds the limit in both directions, an alarm message is uploaded to the power distribution automation system.

[0013] Step 2 described in the present invention adopts the master station centralized control mode. When the distribution automation system receives the forward and reverse overload, voltage limit and distribution network section checkpoint alarms uploaded by the distribution terminal, the distribution automation system decomposes the control quota at different time sections according to the regional power generation forecast curve data and historical load curve data, and forms a distributed resource control plan in three steps, giving priority to adjusting the operation mode, followed by regulating the medium voltage distributed resources, and finally regulating the low voltage distributed resources.

[0014] The line operation adjustment scheme described in step 3 of the present invention is as follows:

[0015] a. According to the control plan issued by the distribution automation master station, the overload is calculated based on the load section, and combined with the contact situation of the controlled medium-voltage line, it is determined whether there are remaining transferable feeders. If so, step b is executed. If not, feedback is given that there is no available line operation adjustment plan, and step 4 is executed;

[0016] b. Sort the transferable feeder schemes according to the conditions that the opposite side equipment does not exceed the limit, the transfer amount is optimal, the operation switch is controllable, and the opposite side load rate is optimal, select the single feeder with the highest ranking as the transfer line, form a single feeder transfer strategy, and execute step c;

[0017] c. Calculate whether the load rate after adjustment has returned to normal: if it has returned to normal, a transfer strategy is formed based on the transfer line and issued for execution, and step d is executed; if the load rate is still abnormal after calculation, step b is repeated, and a single feeder with a higher ranking is selected as the transfer line to form a single line transfer strategy until there are no remaining transferable feeders, and a transfer strategy is formed based on the transfer line and issued for execution, and step d is executed;

[0018] d. After the power transfer strategy is issued and executed, calculate whether the operating section has returned to normal. If it has returned to normal, execute step 1. If it has not returned to normal, execute step 4.

[0019] In step 4 of the present invention, the medium-voltage distributed resources are regulated as follows: the distribution automation system carries out medium-voltage distributed resource regulation in a centralized control mode, forms a control strategy in the order of first regulating medium-voltage energy storage resources, secondly regulating controllable loads, and finally adjusting medium-voltage distributed photovoltaics, issues execution and feeds back the control results, calculates whether the operating section has returned to normal, and if so, executes step 1; if not, executes step 5.

[0020] In step 5 of the present invention, the group control strategy for low-voltage distributed resources is based on the principle of active balance autonomy, and responds to superior control instructions in emergency situations. When there is no superior control instruction, the substation operates in the substation autonomous state, and the substation terminal or edge device assumes the control right, with the substation forward and reverse heavy overload or voltage over-limit as the boundary, to ensure the dynamic balance and stable operation of the substation source and load. When the distribution automation master station issues a control instruction, the edge device carries out output control in the order of energy storage, adjustable load, and distributed photovoltaics. The control ratio is based on the capacity of the existing distributed resources in the substation, responds to the control requirements issued by the distribution automation system, and feeds back the control results. When the superior control is completed, it returns to the autonomous operation state of the substation. After step 5 is completed, all distributed resource control links are completed, and step 1 is executed.

[0021] The present invention is applicable to the formulation of control schemes for low-voltage distributed resources in distribution networks. The strategy adopts the principle of "layered and graded control". It takes whether the medium-voltage line of the distribution network has abnormal conditions such as forward and reverse heavy overloads and voltage bidirectional over-limit as the basis for judgment. It gives priority to adjusting the original operation mode of the line to restore the normal operation of the distribution network. If the control requirements cannot be met, it will switch to regulating medium-voltage distributed resources to restore the normal load rate of the line. If the requirements are still not met, it will switch to low-voltage distributed resource group adjustment until the line load rate is completely restored to normal. The present invention can realize three different levels of control strategies through three different judgment logics, and realize the optimal control scheme of low-voltage distributed resources in distribution networks under different scenarios. The present invention restores the abnormal line load rate by adjusting the medium-voltage line operation mode, medium-voltage distributed resources, and low-voltage distributed resources in turn, which can improve the vacancy of "blind adjustment" of existing distributed resource control, improve the control efficiency of distributed resources in distribution networks, and create significant social and economic benefits. Compared with the prior art, the present invention can reduce the negative impact of distributed energy on the distribution network and improve the distributed energy consumption capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the distribution network operation monitoring and control strategy of the present invention;

[0023] Figure 2 It is a schematic diagram of the low-voltage area operation control strategy of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention.

[0025] Step 1: The distribution terminal monitors the operating status of the medium voltage distribution network (medium voltage data section monitoring), with the occurrence of forward and reverse heavy overload or bidirectional voltage over-limit as the boundary, and uploads an alarm signal when abnormal data is monitored;

[0026] Step 2: After receiving the alarm information, the master station of the distribution automation system starts to start the control strategy;

[0027] Step 3: The first level is that the master station of the distribution automation system adjusts the operation mode of the medium voltage distribution network, generates a line operation adjustment plan according to the medium voltage line connection status and overload, and if the operation section returns to normal after the operation mode adjustment, returns to step 1; if there are no remaining transferable feeders or the line operation section is still abnormal after the line operation mode adjustment, execute step 4;

[0028] Step 4: The second level is that the master station of the distribution automation system regulates the medium voltage distributed resources. If the operation section returns to normal after the medium voltage distributed resources are regulated, return to step 1; if the line operation section is still abnormal after regulation, execute step 5;

[0029] Step 5: The third level is that the distribution automation master station sends the control strategy to the intelligent fusion terminal edge device in the substation based on the access status of low-voltage distributed resources within the range, performs group adjustment on the low-voltage distributed resources, and returns to step 1 after the adjustment is completed.

[0030] Figure 1 The figure shows a flow chart of the medium-voltage distribution network operation monitoring and control strategy of the present invention. The method takes forward and reverse heavy overloads of the flow, voltage exceeding the limit, and distribution network section checkpoints as boundaries: when the distribution automation system receives the alarm information uploaded by the distribution terminal, the distribution automation system decomposes the control quota at different time sections according to the regional power generation forecast curve data and the historical load curve data, and forms a distributed resource control plan in three steps, giving priority to adjusting the operation mode, followed by regulating the medium-voltage distributed resources, and finally regulating the low-voltage distributed resources.

[0031] The operation mode of the medium voltage distribution network described in step 3 of the present invention is adjusted as follows:

[0032] a. According to the control plan issued by the distribution automation master station, the overload is calculated based on the load section, and combined with the contact situation of the controlled medium-voltage line, it is determined whether there are remaining transferable feeders. If so, step b is executed. If not, feedback is given that there is no available line operation adjustment plan, and step 4 is executed;

[0033] b. Sort the transferable feeder schemes according to the conditions that the opposite side equipment does not exceed the limit, the transfer amount is optimal, the operation switch is controllable, and the opposite side load rate is optimal, select the single feeder with the highest ranking as the transfer line, form a single feeder transfer strategy, and execute step c;

[0034] c. Calculate whether the load rate after adjustment has returned to normal: if it has returned to normal, a transfer strategy is formed based on the transfer line and issued for execution, and step d is executed; if the load rate is still abnormal after calculation, step b is repeated, and a single feeder with a higher ranking is selected as the transfer line to form a single line transfer strategy until there are no remaining transferable feeders, and a transfer strategy is formed based on the transfer line and issued for execution, and step d is executed;

[0035] d. After the power transfer strategy is issued and executed, calculate whether the operating section has returned to normal. If it has returned to normal, execute step 1. If it has not returned to normal, execute step 4.

[0036] In step 4 of the present invention, the medium-voltage distributed resources are regulated as follows: the distribution automation system carries out medium-voltage distributed resource regulation in a centralized control mode, forms a control strategy in the order of first regulating medium-voltage energy storage resources, secondly regulating controllable loads, and finally adjusting medium-voltage distributed photovoltaics, issues execution and feeds back the control results, calculates whether the operating section has returned to normal, and if so, executes step 1; if not, executes step 5.

[0037] The medium-voltage side distributed resources of the present invention upload data to the distribution automation master station and the dispatching automation master station, and converge at the distribution automation master station. The distribution automation system is used as the control core to generate and decompose control instructions and issue them. The centralized new energy stations and the medium-voltage distributed resources directly connected to the dispatching automation are forwarded to the dispatching automation system for execution; those connected to the distribution automation system via three remote switches are directly executed by the distribution automation system.

[0038] Figure 2 The diagram shows the operation and control strategy of the low-voltage substation of the present invention. The low-voltage distributed resources are based on the principle of active balance and autonomy, and respond to the superior control instructions in an emergency. The low-voltage distributed resources are based on the principle of active balance and autonomy, and respond to the superior control instructions in an emergency. In the absence of superior control instructions, the substation operates in the substation autonomous state, and the substation terminal or edge device assumes the control right, with the substation forward and reverse heavy overload or voltage over-limit as the boundary, to ensure the dynamic balance of source and load and stable operation of the substation. In the scenario where the distribution automation master station issues a control instruction, the edge device carries out output control in the order of energy storage, adjustable load, and distributed photovoltaics. The control ratio is based on the capacity of the existing distributed resources in the substation, responds to the control requirements issued by the distribution automation system, and feeds back the control results. When the superior control is completed, it returns to the autonomous operation state of the substation.

[0039] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A distributed resource control strategy for a distribution network, characterized in that Includes steps: Step 1: The distribution terminal monitors the operating status of the medium voltage distribution network, taking the occurrence of forward and reverse heavy overload or voltage exceeding the limit as the boundary, and uploads an alarm signal when abnormal data is monitored; Step 2: After receiving the alarm information, the master station of the distribution automation system starts to generate and issue distributed resource control strategies in three levels; Step 3: The first level is that the master station of the distribution automation system adjusts the operation mode of the medium voltage distribution network, generates a line operation adjustment plan according to the medium voltage line connection status and overload, and if the operation section returns to normal after the operation mode adjustment, returns to step 1; if there are no remaining transferable feeders or the line operation section is still abnormal after the line operation mode adjustment, execute step 4; Step 4: The second level is that the master station of the distribution automation system regulates the medium voltage distributed resources. If the operation section returns to normal after the medium voltage distributed resources are regulated, return to step 1; if the line operation section is still abnormal after regulation, execute step 5; Step 5: The third level is that the distribution automation master station sends the control strategy to the intelligent fusion terminal edge device in the substation based on the access status of low-voltage distributed resources within the range, and regulates the low-voltage distributed resources. After the regulation is completed, it returns to step 1.

2. The distributed resource control strategy for the power distribution network according to claim 1, characterized in that: The step 1 that the distribution terminal monitors the operating status of the medium-voltage distribution network is as follows: the medium-voltage section data is continuously monitored through the distribution terminal, and when an abnormal situation occurs in which the line is heavily overloaded in the forward and reverse directions or the voltage exceeds the limit in both directions, an alarm message is uploaded to the distribution automation system.

3. The distributed resource control strategy for the power distribution network according to claim 1, characterized in that: The step 2 generates and issues distributed resource control strategies in three levels: adopting the master station centralized control mode, when the distribution automation system receives the forward and reverse overload, voltage limit, and distribution network section checkpoint alarms uploaded by the distribution terminal, the distribution automation system decomposes the control quota at different time sections according to the regional power generation forecast curve data and historical load curve data, and forms a distributed resource control plan in three steps, giving priority to adjusting the operation mode, followed by regulating medium-voltage distributed resources, and finally regulating low-voltage distributed resources.

4. The distributed resource control strategy for the power distribution network according to claim 1, characterized in that: The line operation adjustment scheme described in step 3 is as follows: a. According to the control plan issued by the distribution automation master station, the overload is calculated based on the load section, and combined with the contact situation of the controlled medium-voltage line, it is determined whether there are remaining transferable feeders. If there are, step b is executed. If there are no available line operation adjustment plans, step 4 is executed; b. Sort the transferable feeder schemes according to the conditions that the opposite side equipment does not exceed the limit, the transfer amount is optimal, the operation switch is controllable, and the opposite side load rate is optimal, select the single feeder with the highest ranking as the transfer line, form a single feeder transfer strategy, and execute step c; c. Calculate whether the load rate after adjustment has returned to normal: if it has returned to normal, a transfer strategy is formed based on the transfer line and issued for execution, and step d is executed; if the load rate is still abnormal after calculation, step b is repeated, and a single feeder with a higher ranking is selected as the transfer line to form a single line transfer strategy until there are no remaining transferable feeders, and a transfer strategy is formed based on the transfer line and issued for execution, and step d is executed; d. After the power transfer strategy is issued and executed, calculate whether the operating section has returned to normal. If it has returned to normal, execute step 1. If it has not returned to normal, execute step 4.

5. The distributed resource control strategy for the power distribution network according to claim 1, characterized in that: In step 4, the medium-voltage distributed resources are regulated as follows: the distribution automation system carries out medium-voltage distributed resource regulation in a centralized control mode, forms a control strategy in the order of first regulating medium-voltage energy storage resources, secondly regulating controllable loads, and finally adjusting medium-voltage distributed photovoltaics, issues execution and feeds back the control results, calculates whether the operating section has returned to normal, and if so, executes step 1; if not, executes step 5.

6. The distributed resource control strategy for the power distribution network according to claim 1, characterized in that: The regulation of low-voltage distributed resources in step 5 is as follows: low-voltage distributed resources are based on the principle of active balance autonomy and respond to superior regulation instructions in emergency situations; When there is no superior control instruction, the substation operates in the substation autonomous state, and the substation terminal or edge device assumes the control right, with the forward and reverse heavy overload or voltage exceeding the limit of the substation as the boundary, to ensure the dynamic balance of source and load and stable operation of the substation; when the distribution automation master station issues a control instruction, the edge device carries out output control in the order of energy storage, adjustable load, and distributed photovoltaic. The control ratio is based on the capacity of the existing distributed resources in the substation, responds to the control requirements issued by the distribution automation system, and feeds back the control results. When the superior control is completed, it returns to the autonomous operation state of the substation. After step 5 is completed, all distributed resource control links are completed, and step 1 is executed.

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