Solar Farm Inverter Reactive Power Control for Feeder Voltage Limits
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Solution Overview
Problem
The increasing penetration of distributed generation (DG) systems, particularly wind farms, causes voltage fluctuations and reverse power flow, leading to excessive feeder voltages that exceed utility limits, necessitating expensive voltage regulation devices like SVC or STATCOM.
Innovation Solution
Utilize solar farm inverters as STATCOMs to dynamically control reactive power, especially at night when they are not producing real power, to regulate feeder voltages and enhance system stability, damping, and power oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If distributed generation systems (wind farms) are increased to meet energy demands, then power generation capacity is improved, but voltage fluctuations and reverse power flow cause excessive feeder voltages that exceed utility limits
Solution Approach 1:
The solar farm inverter is designed to perform multiple functions: generating real power during daytime and providing reactive power compensation at night. By making the inverter universal, the system can accommodate both power generation and voltage regulation needs without requiring separate dedicated equipment for each function, thus resolving the contradiction between increasing DG capacity and maintaining voltage stability
Solution Approach 2:
The solar farm inverter serves the dual purpose of power generation and voltage regulation within the same system. During nighttime when real power generation is not needed, the inverter automatically switches to provide reactive power compensation, allowing the system to self-regulate voltage without external intervention or additional dedicated compensation equipment
2Object-affected harmful factors
If expensive voltage regulation devices like SVC or STATCOM are installed to control voltage, then voltage stability is improved, but system cost and device complexity increase
Solution Approach 1:
Instead of installing separate dedicated voltage regulation devices, the invention makes the existing solar farm inverter perform both power generation and voltage regulation functions. This eliminates the need for additional expensive equipment like SVC or STATCOM, reducing system cost and complexity while maintaining voltage stability
Solution Approach 2:
The solar farm system provides its own voltage regulation capability through the inverter's reactive power compensation function at night, making the system self-sufficient and eliminating the need for external expensive voltage regulation equipment
3Object-affected harmful factors
If solar farm inverters are utilized as STATCOM at night, then voltage control and system stability are improved, but inverter capacity is reduced during daytime real power generation
Solution Approach 1:
The inverter operates in different modes during different time periods: real power generation during daytime and reactive power compensation at night. This periodic switching allows the system to optimize performance for each time period without compromising overall productivity, as the inverter is utilized fully in each mode according to temporal needs
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective voltage control and increased hosting capacity for DG systems by utilizing underutilized solar farm inverter capacity, reducing the need for expensive voltage regulation devices and enhancing system stability and power transfer limits.
Implementation Method 1
a voltage inverter enabling the distributed power generation source to dynamically control reactive power
Implementation Method 2
a control means that operates the voltage inverter, wherein a voltage at the point of common coupling is regulated by the control means
Data Source
AI summary
A method and system for controlling a photovoltaic solar power generation source operatively coupled to a power grid system at a point of common coupling (PCC) to perform a plurality of dynamic reactive power control based functions including: reactive power set point control, power factor control, and voltage control, when its primary energy source is not available, and available. Voltage control may also prevent PCC voltage from violating a voltage limit caused by real power generation from itself or by real power generation from an additional distributed power generation source operatively connected to said power grid system, or by both. Controlling a battery energy storage based distributed power generation source operatively coupled to a power grid system at a PCC to perform reactive power set point control, power factor control, and voltage control, during both the conditions when its primary energy source is not available, and available is also provided.