Voltage Reactive Power Control with Correction Functions
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Solution Overview
Problem
Existing voltage/reactive power control methods, such as central and hierarchical control, face challenges with data transmission and processing delays, especially during abrupt load changes, and struggle to maintain optimal reactive power balance due to system condition changes.
Innovation Solution
A voltage/reactive power control system that divides the power system into local systems with a central control unit setting optimal power flow calculations and generating correction functions using past history data, allowing for real-time adjustments by local control apparatuses to ensure control target values are met with minimal transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If central control method is used to collect and process information on the entire power system, then optimal voltage and reactive power control can be achieved, but control delay increases particularly during abrupt load changes
Solution Approach 1:
The power system is divided into multiple system regions with monitoring points, where each region performs local optimization calculations independently. This segmentation allows parallel processing of control decisions across different regions, reducing the overall control delay while maintaining optimal control accuracy through distributed optimization.
Solution Approach 2:
The system performs feedforward control by predicting voltage fluctuations using historical data before actual load changes occur. By pre-calculating control actions based on predicted voltage changes, the system reduces control delay and ensures faster response to abrupt load changes.
2Reliability
If hierarchical control method is used to divide power system by voltage class, then voltage control can be performed in an emphatic manner, but data transmission and processing load increases
Solution Approach 1:
The system divides the power system into multiple system regions at the same voltage class, with each region independently performing optimization calculations. This segmentation simplifies the hierarchical structure by eliminating the need for multi-level voltage class hierarchy while maintaining effective voltage control through distributed regional optimization.
Solution Approach 2:
Each system region autonomously performs its own optimization calculation and control decision-making using local monitoring data. This self-service approach reduces the data transmission and processing load on central or upper-level control systems, as each region independently manages its own voltage and reactive power control.
3Productivity
If individual control method is used to divide power system into sub regions, then control can be decentralized, but reactive power balance cannot be necessarily optimized
Solution Approach 1:
The system combines the advantages of individual control with centralized optimization by having each system region perform local optimization calculations that consider both local conditions and overall system reactive power balance. This merging approach ensures fast decentralized control response while maintaining optimal reactive power balance through coordinated optimization across all regions.
Data Source
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AI summary
There is provided a voltage/reactive power control device, method, and a voltage/reactive power control system that allow a proper control even with a control delay or in a situation where the system conditions at the time of setting the voltage reference value may not be always reproduced. A voltage/reactive power control system is applied to a power system in which a monitoring point is set in a local system divided as appropriate from the power system and the local system includes a voltage/reactive power control device capable of adjusting voltage and reactive power at the monitoring point. The voltage/reactive power control system includes: a central control unit that sets a control target value of the voltage and reactive power at the monitoring point in the local system based on optimal power flow calculation using total system data on the power system, generates a correction function to correct the control target value in accordance with a change in state of the power system relating to the monitoring point by using past history information on the states of the power system, and outputs the control target value and at least one or more correction functions; a local control apparatus that, when the control target value is different from system data on the local system, uses the correction function to calculate a controlled variable for the voltage/reactive power control device necessary to attain the control target value; and a device control apparatus that controls the voltage/reactive power control device in accordance with the controlled variable from the local control apparatus.