DER Terminal Voltage Control for Grid PCC Regulation
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Solution Overview
Problem
Distributed energy resources (DERs) like wind turbine generators face challenges in regulating voltage at the point of common coupling due to complexities in reactive power control, especially for small units, and operator confusion regarding reactive power conventions, which can lead to overvoltage issues and equipment trips.
Innovation Solution
An open-loop voltage control system that adjusts DER terminal voltage inversely with point of common coupling (PCC) voltage, eliminating the need for closed-loop feedback and reactive power control, using a table or equation-based relationship to simplify voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reactive power control is used to regulate voltage at PCC, then voltage regulation capability is improved, but operator complexity and confusion increase due to reactive power conventions
Solution Approach 1:
The patent extracts the voltage regulation function from reactive power control and implements it through direct terminal voltage control. Instead of controlling reactive power to achieve voltage regulation, the system directly controls the terminal voltage of the DER, separating the voltage regulation function from reactive power management and eliminating operator confusion about reactive power conventions.
Solution Approach 2:
The patent changes the control parameter from reactive power to terminal voltage. By directly controlling the terminal voltage parameter rather than controlling reactive power indirectly, the system achieves voltage regulation while simplifying operator interaction and eliminating confusion related to reactive power conventions and droop characteristics.
2Reliability
If reactive droop control is implemented, then voltage regulation efficacy is improved, but device complexity increases due to closed-loop feedback requirements
Solution Approach 1:
The patent segments the control system into simple terminal voltage measurement and direct control, eliminating the need for complex closed-loop feedback mechanisms. Instead of implementing full reactive droop control with continuous feedback, the system uses a simplified approach that directly adjusts terminal voltage based on measured values, reducing device complexity while maintaining regulation efficacy.
Solution Approach 2:
The patent replaces complex, expensive closed-loop feedback control systems with a simpler, more economical terminal voltage control mechanism. The simplified control approach achieves the necessary voltage regulation without requiring elaborate feedback infrastructure, reducing both device complexity and implementation cost.
3Ease of operation
If DER terminal voltage is controlled inversely with PCC voltage, then voltage regulation simplicity is improved, but control precision may be affected
Solution Approach 1:
The patent inverts the traditional control approach by controlling terminal voltage inversely with PCC voltage rather than using direct feedback from PCC voltage. This inversion simplifies the control logic while maintaining adequate precision through proper scaling and coordination of DER voltage adjustments that collectively achieve the desired PCC voltage regulation.
Data Source
AI summary
A system and method for regulating a voltage at a point of common coupling (35) (PCC) of a distributed energy resource farm (1) connected to an electrical power grid (37). The distributed energy resource farm includes a plurality of connected distributed energy resources (2, 3) each supplying a terminal voltage. The system includes a component (50) for measuring a PCC voltage at the PCC, and another component (39, 41) for determining a first value based on a relationship between a scheduled voltage at the PCC and the measured PCC voltage relative to a dead band voltage region (66). A further component (39, 41) regulates the voltage at the point of common coupling by controlling the terminal voltage of each one of the plurality of distributed energy resources in response to the relationship between the scheduled voltage and the measured voltage at the PCC.