CN103138269B - Layered and distributed network voltage regulator control system and method based on active mechanism - Google Patents

Abstract

The invention discloses a layered distributed distribution network voltage control system based on an active mechanism, including: a reactive voltage controller for a single branch, a coordinated voltage controller for a local area, and an active distribution network for the entire distribution network. The grid voltage management subsystem; the active distribution network voltage management subsystem determines the voltage control index according to the active power distribution of the distribution network; after the voltage exceeds the limit, the reactive voltage controller will adjust the voltage limit locally. If it fails, the coordinated voltage controller is adjusted on the basis of comprehensive consideration of voltage fluctuations and intermittent energy grid-connected and off-grid plans, and the two cooperate to achieve voltage over-limit recovery based on an active mechanism. At the same time, the invention also discloses a control method corresponding to the above system. Under the premise of satisfying the constraints of the distribution network, the system and method realize the active control of the voltage exceeding the limit of the distribution network.

Description

System and method for voltage regulation and control of hierarchical distributed distribution network based on active mechanism

technical field

The invention relates to the technical field of smart grid voltage control, in particular to an active mechanism-based hierarchical distributed distribution network voltage regulation system and method.

Background technique

In recent years, with the access of distributed energy resources (DER, Distributed Energy Resource), especially new renewable energy sources (RES, Renewable Energy Resources) such as wind energy and solar energy, the traditional radial distribution network with one-way flow of power flow has begun Gradually transforming into a complex network with two-way flow of currents. In response to this situation, the WG C6.19~WG C6.22 Working Group of the Power Distribution and Distributed Generation (C6) Technical Committee of the International Conference on Large Power Grids (CIGRE) proposed the concept of active distribution systems. The active distribution network is a system composed of micro-power sources, loads, energy storage systems, and control devices. It is a single controllable unit for the large power grid, which can realize the highly reliable supply of various energy forms.

At present, there are mainly two methods for active distribution network voltage control technology:

(1) Voltage control based on "trigger type", which is characterized by directly triggering the predetermined control process to adjust according to the value collected in real time through the setting of dead zone and threshold value;

(2) Voltage control based on overall coordination. This control strategy is based on the values collected in real time, while taking into account the characteristics of the network structure. Through a certain algorithm, the action modes of all control devices are output uniformly, and then the control commands are issued. Issued.

However, there are considerable constraints in the two technologies mentioned at this stage. The "trigger" voltage control strategy has the obvious advantages of fast action speed and less resource consumption, but it is difficult to choose the dead zone range. If the sensitivity is too high, the equipment will vibrate repeatedly. If the dead zone is set too large, it will lead to failure to respond in time when some voltages exceed the limit. Moreover, the core idea of the "trigger" voltage control strategy is still passive and cannot be adapted to Active distribution network is characterized by "optimized control based on active mechanism". The control strategy based on overall coordination needs to control the entire power grid, so it needs network topology information, real-time voltage values of each node, distributed generation (DG, Distributed Generation), capacitors, and current status of on-load tap changer (OLTC) taps. The support of a large amount of data such as state and adjustable range will lead to excessive calculation and it is difficult to meet the real-time requirements. At the same time, there are far more controllable elements in the active distribution network than in the traditional distribution network, in which DG and reactive power compensation (SVC, Static Var Compensator) change continuously, while the states of capacitors and OLTC are discrete, so The overall coordination control problem is a very complex mixed integer programming problem, which brings great difficulties to the selection of algorithms.

Therefore, it is necessary to improve the voltage regulation method and system of distributed distribution network.

Contents of the invention

The purpose of the present invention is to provide a layered distributed distribution network voltage regulation system and method based on an active mechanism, so as to optimize the overall coordinated control of the active distribution network voltage.

In order to achieve the above objectives, the present invention provides a hierarchical distributed distribution network voltage control system based on an active mechanism, the system includes: a reactive voltage controller, a coordinated voltage controller, and an active distribution network voltage management subsystem. The reactive voltage controller is oriented to a single branch in the distribution network, the coordinated voltage controller is oriented to a local area including multiple branches in the distribution network, and the active distribution network voltage management subsystem is oriented to the entire distribution network net; among them,

The active distribution network voltage management subsystem is used to calculate the voltage control index according to the current active power and network topology of the distribution network, and interact the voltage control index with the reactive voltage controller;

The reactive voltage controller is used to control and adjust the voltage locally when the voltage exceeds the limit and the voltage value at the top of the branch is within the range of the voltage control index, so that the voltage values of all nodes of the branch are within the required range; If the branch vertex voltage value is not within the range of the voltage control index, send an assisting control instruction to the active distribution network voltage management subsystem;

The coordinated voltage controller is used to cooperate with the reactive voltage controller to complete voltage coordinated control when the voltage value of the branch apex is not within the range of the voltage control index, so that the voltages of all nodes of all branches of the distribution network The value is within the required range; wherein, the voltage adjustment value of the coordinated voltage controller is calculated by the active distribution network voltage management subsystem and sent to the coordinated voltage controller.

Preferably, the reactive voltage controller controls and adjusts the voltage locally through a first controllable unit.

Preferably, the first controllable unit is a reactive unit.

Preferably, the first controllable unit includes a distributed power generation unit, a reactive power compensation device and a controllable load.

Preferably, the coordinated voltage controller implements voltage coordinated control through a second controllable unit.

Preferably, the second controllable unit is an adjustable transformer, and the adjustment of the taps of the adjustable transformer only affects the voltage values of all branches under the second controllable unit without affecting their reactive power value.

Preferably, the voltage adjustment value of the coordinated voltage controller is calculated by the active distribution network voltage management subsystem based on the active mechanism algorithm, and through the prediction of voltage fluctuations, while comprehensively considering intermittent energy grid connection and off-grid Plan to select the appropriate adjustment value to achieve optimal control of the voltage of the entire distribution network.

At the same time, in order to achieve the above purpose, the present invention also provides an active mechanism-based hierarchical distributed distribution network voltage regulation method, which uses the above-mentioned active mechanism-based hierarchical distributed distribution network voltage regulation system to control the grid voltage Regulating, the method includes the steps of:

Step 1): The active distribution network voltage management subsystem calculates the voltage control index according to the current active power and network topology of the distribution network, and interacts with the reactive voltage controller for the voltage control index;

Step 2): When the voltage exceeds the limit, if the voltage value at the top of the branch is within the range of the voltage control index, the reactive voltage controller will control and adjust the voltage locally so that the voltage values of all nodes of the branch are within the required within the range; if the voltage value at the apex of the branch is not within the range of the voltage control index, go to step 3);

Step 3): The reactive voltage controller sends an assisting control command to the active distribution network voltage management subsystem, and the coordinated voltage controller performs voltage coordinated control, so that all nodes of all branches of the distribution network The voltage value is within the required range.

Preferably, the step 3) specifically includes the following steps:

Step 31): The reactive voltage controller sends an assisting control command to the active distribution network voltage management subsystem, and the active distribution network voltage management subsystem calculates the voltage adjustment value of the coordinated voltage controller and The voltage adjustment value is issued to the coordinated voltage controller;

Step 32): The coordinated voltage controller controls and adjusts the branch voltages according to the voltage adjustment value, so that the peak voltage values of all branches are within the range of the voltage control index; if this step is completed, the power distribution If the voltage values of all nodes of all branches of the distribution network are within the required range, the adjustment ends; if after this step is completed, there are still some branch voltages in the distribution network that exceed the limit, then go to step 33);

Step 33): The reactive voltage controller controls and adjusts the voltage locally, so that the voltage values of all nodes of the branch are within the required range.

Preferably, the reactive voltage controller controls and adjusts the voltage locally through a first controllable unit.

Preferably, the first controllable unit is a reactive unit.

Preferably, the first controllable unit includes a distributed power generation unit, a reactive power compensation device and a controllable load.

Preferably, the coordinated voltage controller implements voltage coordinated control through a second controllable unit.

Preferably, the second controllable unit is an adjustable transformer, and the adjustment of the taps of the adjustable transformer only affects the voltage values of all branches under the second controllable unit without affecting their reactive power value.

Preferably, the voltage adjustment value of the coordinated voltage controller is calculated by the active distribution network voltage management subsystem based on the active mechanism algorithm, and through the prediction of voltage fluctuations, while comprehensively considering intermittent energy grid connection and off-grid Plan to select the appropriate adjustment value to achieve optimal control of the voltage of the entire distribution network.

Compared with the prior art, the present invention has the following advantages and positive effects due to the adoption of the above technical solutions:

1) The present invention comprehensively utilizes the controllable resources of the distribution network. Compared with the traditional "trigger" voltage control mode, it avoids the selection of dead zones, has high sensitivity, and does not repeatedly oscillate and adjust the equipment;

2) The present invention uses a multi-level and layered mode to restore the voltage beyond the limit. Compared with the traditional control strategy based on overall coordination, it avoids the huge amount of calculation for the voltage restoration of the entire power grid, can ensure rapid voltage restoration, and effectively increase scope of management;

3) The present invention adopts an algorithm based on an active mechanism to realize active identification of voltage fluctuations and active adaptation to grid-connected and off-grid intermittent energy sources, and realizes voltage optimization control based on active mechanisms for active distribution networks;

4) The present invention interacts with the active distribution network voltage management subsystem, the reactive voltage controller, and the coordinated voltage controller to make the recovery mode of the voltage exceeding the limit more flexible. When the distribution network undergoes secondary expansion , only need to increase the reactive voltage controller, thus making it easier to expand the scope of management.

Description of drawings

Fig. 1 is a schematic structural diagram of a hierarchical distributed distribution network voltage regulation system based on an active mechanism provided by an embodiment of the present invention;

Fig. 2 is the distribution network structure diagram of Fig. 1;

Fig. 3 is a flowchart of a method for regulating voltage in a hierarchical distributed distribution network based on an active mechanism provided by an embodiment of the present invention.

Detailed ways

The active mechanism-based layered distributed distribution network voltage regulation system and method proposed by the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Advantages and features of the present invention will be apparent from the following description and claims. It should be noted that all the drawings are in very simplified form and use imprecise ratios, which are only used for the purpose of conveniently and clearly assisting in describing the embodiments of the present invention.

Please refer to Figures 1 to 2, as shown in Figures 1 to 2, the active mechanism-based hierarchical distributed distribution network voltage regulation system provided by the embodiment of the present invention includes: a reactive voltage controller 2, a coordinated voltage controller 3 and the active distribution network voltage management subsystem 1, the reactive voltage controller 2 is oriented to a single branch in the distribution network, the coordinated voltage controller 3 is oriented to a local area including multiple branches in the distribution network, and the active distribution network The grid voltage management subsystem 1 faces the entire distribution network, and the reactive voltage controller 2 and coordination voltage controller 3 can interact with the active distribution network voltage management subsystem 1. The two-way arrow in Figure 2 is Indicates mutual information interaction. The reactive voltage controller 2, the coordinating voltage controller 3, and the active distribution network voltage management subsystem 1 work together to complete the recovery of the active distribution network voltage from the level of the distribution network. in:

The active distribution network voltage management subsystem 1 is used to calculate the voltage control index 4 according to the current active power and network topology of the distribution network, and interact with the reactive voltage controller 2 for the voltage control index 4;

The reactive voltage controller 2 is used to control and adjust the voltage on the spot when the voltage exceeds the limit and the voltage value of the apex of the branch is within the range of the voltage control index 4, so that the voltage values of all nodes of the branch are within the required range; specifically The ground reactive voltage controller 2 controls and regulates the voltage on the spot through a first controllable unit; preferably, the first controllable unit is a reactive unit; preferably, the first controllable unit can be distributed Type generating unit or reactive power compensation device or controllable load, etc. If the voltage value at the vertex of the branch is not within the range of the voltage control index 4, an assisting control command is sent to the active distribution network voltage management subsystem 1;

The coordinated voltage controller 3 is used to cooperate with the reactive voltage controller 2 to complete the voltage coordinated control when the voltage value of the branch apex is not within the range of the voltage control index 4, so that the voltage values of all nodes of all branches of the distribution network are within the required range. Within the range; wherein, the voltage adjustment value of the coordinated voltage controller 3 is calculated by the active distribution network voltage management subsystem 1 and sent to the coordinated voltage controller 3 . Specifically, the coordinated voltage controller 3 sends adjustable information to the active distribution network voltage management subsystem 1, and the active distribution network voltage management subsystem 1 integrates the voltage control index 4 and the adjustable information, and calculates based on the active mechanism algorithm, And through the prediction of voltage fluctuations and comprehensive consideration of intermittent energy grid-connected and off-grid plans to select the appropriate adjustment value, the optimal control of the voltage of the entire distribution network is realized.

Wherein, the coordinated voltage controller 3 completes the voltage coordinated control by a second controllable unit; preferably, the second controllable unit is an adjustable transformer 21, as shown in Figure 2; the tap of the adjustable transformer 21 The adjustment only affects the voltage values of all branches under the second controllable unit without affecting their reactive power values.

From the above description, it can be seen that the reactive voltage controller 2 proposed by the present invention performs comprehensive scheduling and management on the power generation units such as local reactive power compensation equipment and distributed power generation equipment with adjustable power factor, so as to realize rapid recovery on the spot when the voltage exceeds the limit. If the deviation is too large, request the upper layer to assist in the control; while the coordinated voltage controller 3 will affect the voltage of all nodes under the branch. The controller 2 cooperates to complete the voltage recovery; the active distribution network voltage management subsystem 1 is used to calculate the voltage control index 4 and the voltage adjustment value of the coordinated voltage controller 3 .

Please continue to refer to Figure 3, Figure 3 is a flow chart of the active mechanism-based layered distributed distribution network voltage regulation method provided by the embodiment of the present invention, as shown in Figure 3, the present invention also provides a layered active mechanism-based The distributed distribution network voltage control method includes the following steps:

S1: The active distribution network voltage management subsystem calculates the voltage control index according to the current active power of the distribution network and the network topology, and interacts with the reactive voltage controller for the voltage control index;

Among them, the voltage control index means: when the voltage at the top of the branch is within the range of the voltage control index, the reactive voltage controller can be used to restore the local voltage beyond the limit; when the voltage at the top of the branch exceeds the voltage control index, the Voltage restoration is not possible with reactive voltage controllers. Specifically, the voltage control index can be obtained iteratively through power flow calculation, and this value does not depend on the input status of each reactive device at the moment.

S2: When the voltage exceeds the limit, judge whether the voltage value at the top of the branch is within the range of the voltage control index. The voltage values of all nodes of the branch are within the required range;

Specifically, the reactive power and voltage controller can perform local voltage control by comprehensively dispatching the first controllable units within the scope of the branch, that is, distributed power generation units, reactive power compensation devices (SVC, capacitors) and controllable loads, etc. adjust.

If the voltage value at the top of the branch is not within the range of the voltage control index, the reactive voltage controller sends an assisting control command to the active distribution network voltage management subsystem, requesting the coordinated voltage controller to assist in the completion of voltage over-limit recovery; specifically, it includes the following step:

S31: The reactive voltage controller sends an assisting control command to the active distribution network voltage management subsystem, and the active distribution network voltage management subsystem comprehensive voltage control index interacts with the adjustable information of the coordination voltage controller, and calculates based on the active mechanism algorithm , and select the appropriate voltage adjustment value by predicting the voltage fluctuation and comprehensively considering the intermittent energy grid connection and off-grid plan, and send the voltage adjustment value to the coordinated voltage controller; wherein, the adjustment value can meet the current After the coordinated voltage controller is adjusted according to the adjustment value, the voltage values at the vertices of all branches are within the range of the voltage control index;

S32: The coordinating voltage controller controls and adjusts the branch circuit voltage according to the voltage adjustment value, specifically by controlling its corresponding second controllable unit, that is, the adjustable transformer tap, so that the peak voltage values of all branches are within the specified Within the scope of the voltage control index, the adjustment of the tap of the adjustable transformer only affects the voltage values of all branches under the second controllable unit without affecting their reactive power values; after this step is completed, the voltage overshoot Limit judgment, if after this step is completed, the voltage values of all nodes of all branches of the distribution network are within the required range, then the adjustment is completed, and the recovery of the entire grid voltage beyond the limit is realized; if this step is completed, the distribution network If some branch voltages exceed the limit, then go to step 2) The reactive voltage controller will control and adjust the voltage on the spot, so that the voltage values of all nodes of the branch are within the required range, and realize the recovery of the entire grid voltage beyond the limit .

To sum up, the present invention restores the voltage violation in the distribution network through a multi-level and hierarchical control framework; forms the active distribution network voltage management subsystem as the core, and uses the reactive voltage controller and coordinated voltage The hierarchical distributed multi-level coordinated control represented by the controller comprehensively utilizes various controllable units connected to the distribution network, such as distributed power generation, reactive power compensation devices, controllable loads, and adjustable transformers, to realize distribution based on active mechanisms. Layer distributed voltage over-limit recovery.

The above-mentioned embodiments are only examples for convenience of description, and the scope of rights claimed by the present invention should be based on the scope of the patent application, rather than limited to the embodiments.

Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (15)

1. A hierarchical distributed distribution network voltage control system based on an active mechanism, characterized in that it includes: a reactive voltage controller, a coordinated voltage controller and an active distribution network voltage management subsystem, the reactive voltage The controller is oriented to a single branch in the distribution network, the coordinated voltage controller is oriented to a local area including multiple branches in the distribution network, and the active distribution network voltage management subsystem is oriented to the entire distribution network; wherein, The active distribution network voltage management subsystem is used to calculate the voltage control index according to the current active power and network topology of the distribution network, and interact the voltage control index with the reactive voltage controller; The reactive voltage controller is used to control and adjust the voltage locally when the voltage exceeds the limit and the voltage value at the top of the branch is within the range of the voltage control index, so that the voltage values of all nodes of the branch are within the required range; If the branch vertex voltage value is not within the range of the voltage control index, send an assisting control instruction to the active distribution network voltage management subsystem; The coordinated voltage controller is used to cooperate with the reactive voltage controller to complete voltage coordinated control when the voltage value of the branch apex is not within the range of the voltage control index, so that the voltages of all nodes of all branches of the distribution network The value is within the required range; wherein, the voltage adjustment value of the coordinated voltage controller is calculated by the active distribution network voltage management subsystem and sent to the coordinated voltage controller. 2. The active mechanism-based hierarchical distributed distribution network voltage regulation system according to claim 1, wherein the reactive voltage controller controls and regulates the voltage locally through a first controllable unit. 3. The active mechanism-based hierarchical distributed distribution network voltage regulation system according to claim 2, wherein the first controllable unit is a reactive unit. 4. The active mechanism-based hierarchical distributed distribution network voltage regulation system according to claim 3, wherein the first controllable unit includes a distributed power generation unit, a reactive power compensation device and a controllable load. 5 . The active mechanism-based hierarchical distributed distribution network voltage regulation system according to claim 1 , wherein the coordinated voltage controller completes voltage coordinated control through a second controllable unit. 6 . 6. The hierarchical distributed distribution network voltage control system based on active mechanism as claimed in claim 5, wherein the second controllable unit is an adjustable transformer, and the adjustment of the tap of the adjustable transformer It only affects the voltage values of all branches under the second controllable unit without affecting their reactive power values. 7. The active mechanism-based hierarchical distributed distribution network voltage control system according to claim 1, wherein the voltage adjustment value of the coordinated voltage controller is based on the active distribution network voltage management subsystem The active mechanism algorithm is used for calculation, and the appropriate adjustment value is selected by predicting the voltage fluctuation and comprehensively considering the intermittent energy grid connection and off-grid plan, so as to realize the optimal control of the voltage of the entire distribution network. 8. A hierarchical distributed distribution network voltage regulation method based on an active mechanism, utilizes the hierarchical distributed distribution network voltage regulation system based on an active mechanism as claimed in claim 1 to regulate and control the grid voltage, characterized in that , the method includes the following steps: Step 1): The active distribution network voltage management subsystem calculates the voltage control index according to the current active power and network topology of the distribution network, and interacts with the reactive voltage controller for the voltage control index; Step 2): When the voltage exceeds the limit, if the voltage value of the apex of the branch is within the range of the voltage control index, the reactive voltage controller will control and adjust the voltage locally, so that the voltage values of all nodes of the branch are within the required within the range; if the branch apex voltage value is not within the range of the voltage control index, then proceed to step 3); Step 3): The reactive voltage controller sends an assisting control command to the active distribution network voltage management subsystem, and the coordination voltage controller performs voltage coordination control, so that all nodes of all branches of the distribution network The voltage value is within the required range. 9. The layered distributed distribution network voltage control method based on active mechanism as claimed in claim 8, characterized in that, said step 3) specifically comprises the following steps: Step 31): The reactive voltage controller sends an assisting control instruction to the active distribution network voltage management subsystem, and the active distribution network voltage management subsystem calculates the voltage adjustment value of the coordination voltage controller and The voltage adjustment value is issued to the coordinated voltage controller; Step 32): The coordinated voltage controller controls and adjusts the branch voltages according to the voltage adjustment value, so that the peak voltage values of all branches are within the range of the voltage control index; if this step is completed, the power distribution If all node voltage values of all branches of the distribution network are within the required range, the adjustment ends; if after this step is completed, there are still some branch voltages in the distribution network that exceed the limit, then go to step 33); Step 33): The reactive voltage controller controls and adjusts the voltage locally, so that the voltage values of all nodes of the branches are within the required range. 10. The active mechanism-based hierarchical distributed distribution network voltage regulation method according to claim 8, wherein the reactive voltage controller controls and regulates the voltage locally through a first controllable unit. 11. The active mechanism-based hierarchical distributed distribution network voltage regulation method according to claim 10, wherein the first controllable unit is a reactive unit. 12. The active mechanism-based hierarchical distributed distribution network voltage regulation method according to claim 11, wherein the first controllable unit comprises a distributed power generation unit, a reactive power compensation device and a controllable load. 13. The active mechanism-based hierarchical distributed distribution network voltage regulation method according to claim 8, wherein the coordinated voltage controller completes voltage coordinated control through a second controllable unit. 14. The active mechanism-based hierarchical distributed distribution network voltage control method according to claim 13, wherein the second controllable unit is an adjustable transformer, and the adjustment of the tap of the adjustable transformer It only affects the voltage values of all branches under the second controllable unit without affecting their reactive power values. 15. The active mechanism-based hierarchical distributed distribution network voltage control method according to claim 9, wherein the voltage adjustment value of the coordinated voltage controller is based on the active distribution network voltage management subsystem The active mechanism algorithm is used for calculation, and the appropriate adjustment value is selected by predicting the voltage fluctuation and comprehensively considering the intermittent energy grid connection and off-grid plan, so as to realize the optimal control of the voltage of the entire distribution network.