Distributed Microgrid Controller Reactive Power Coordination
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Solution Overview
Problem
Centralized control approaches for microgrids are costly, complex, and prone to failure, requiring large amounts of control signaling and a central device that can cause the entire system to fail if it malfunctions.
Innovation Solution
A distributed method where each distributed generator in a microgrid is connected to a controller that measures voltage levels, determines parameter values based on these measurements, and communicates with other controllers to establish a sequential order for injecting reactive power, allowing decentralized control of real and reactive power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized control approach is used for assigning real and reactive power references, then coordination of power distribution is improved, but system complexity and cost increase due to requiring a central control device and large amounts of control signaling
Solution Approach 1:
The centralized control function is segmented and distributed to individual generator controllers. Each controller independently determines its own reactive power reference based on local voltage measurements and communicated parameter values, eliminating the need for a central control device and reducing control system complexity while maintaining coordination.
Solution Approach 2:
The system implements a feedback mechanism where each controller measures local voltage, communicates parameter values to other controllers, receives their parameter values, and uses this information to determine sequential order and reactive power references. This distributed feedback loop replaces centralized control signaling.
2Reliability
If centralized control device is used, then power distribution coordination is achieved, but system reliability deteriorates because the entire control system may fail when the central device fails
Solution Approach 1:
The control function is segmented across multiple independent generator controllers rather than concentrated in a single central device. This segmentation ensures that failure of one controller does not cause system-wide control failure, improving reliability while eliminating the central control device requirement.
Solution Approach 2:
Each generator controller performs the same control functions and has equal capability to determine reactive power references. This homogeneous distributed architecture replaces the heterogeneous centralized structure, improving reliability through redundancy while simplifying the control device architecture.
3Device complexity
If distributed control method is used where each generator measures voltage and determines parameter values, then control system cost and complexity are reduced, but reactive power coordination may deteriorate without centralized signaling
Solution Approach 1:
Each controller measures local voltage and communicates parameter values to other controllers, creating a distributed feedback mechanism. This feedback loop enables automatic coordination of reactive power injection without centralized signaling, maintaining coordination reliability while reducing control system complexity and cost.
Solution Approach 2:
Each generator controller independently determines its own reactive power reference based on local measurements and communicated information, without requiring commands from a central controller. This self-service approach eliminates complex centralized signaling while maintaining coordination through the sequential order mechanism.
4Quantity of substance
If sequential order for reactive power injection is determined based on communicated parameter values, then control signaling is reduced compared to centralized control, but control precision may worsen due to decentralized decision-making
Solution Approach 1:
The sequential order determination uses feedback from communicated parameter values (voltage measurements and reactive current injection capacities) to enable precise decentralized control. Each controller adjusts its reactive power reference based on this feedback, achieving control precision comparable to centralized control while reducing signaling requirements.
Solution Approach 2:
The system dynamically changes control parameters (reactive power references) based on measured voltage levels and communicated parameter values. This parameter adaptation enables precise control in a decentralized manner, maintaining control precision while reducing the need for extensive control signaling.
Data Source
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AI summary
A distributed method is provided for controlling electrical power in a microgrid (11), wherein a plurality of distributed generators (13a-d) supply electrical power to the microgrid, and each of the distributed generators is connected to a controller (15a-d) for controlling the real and reactive output power from the distributed generator. The method comprising the steps of measuring (31), for each of the distributed generators, a voltage level at a measuring point (17a; 17b) associated with that distributed generator and forwarding the measured voltage level to the controller connected to that distributed generator; determining (32), for each of the controllers, a parameter value related to the received measured voltage level and/or related to a reactive current injection capacity of the distributed generator connected to that controller;communicating (33), from each of the controllers, its determined parameter value to each other ones of the controllers; determining (34) a sequential order in which the controllers are to control the distributed generators to inject reactive power into the microgrid based on the communicated parameter values; and controlling (35) the distributed generators to inject reactive power into the microgrid by means of the controllers in the determined sequential order.