Gridforming Inverter Curtailment Control for Stable PV Output
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Solution Overview
Problem
Existing photovoltaic power plants face challenges in responding to curtailment commands due to weak grid stability, leading to tripping or shutdown, which results in economic loss and inefficiency, especially when battery storage is unavailable and smart inverters are not installed.
Innovation Solution
A gridforming type curtailment control system comprising a photovoltaic inverter and a gridforming inverter connected via a DC link device, with an energy storage device, allowing continuous power output and inertia control during grid disturbances, enabling voltage source control and curtailment management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photovoltaic power plants are tripped or shut down due to grid stability issues, then grid stability is improved, but power generation continuity is lost and economic losses occur
Solution Approach 1:
The system divides the inverter function into two independent units: a photovoltaic inverter for power conversion and a gridforming inverter for voltage and frequency control. This segmentation allows the gridforming inverter to maintain grid stability while the photovoltaic inverter continues power generation, resolving the contradiction between stability and continuity.
Solution Approach 2:
The gridforming inverter acts as an intermediary between the photovoltaic power plant and the power grid. It provides voltage source control and inertia response to maintain grid stability during disturbances, enabling continuous power generation without tripping while preventing stability issues.
2Device complexity
If photovoltaic inverters operate without battery storage or smart inverter functions, then device complexity is reduced, but ability to respond to curtailment commands is limited
Solution Approach 1:
The gridforming inverter provides multiple functions including voltage source control, inertia response, and curtailment management in a single device. This multi-functionality enables standard inverters to respond to curtailment commands and maintain grid stability without requiring battery storage or complex smart inverter features.
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
The system ensures continuous photovoltaic power generation and efficient utilization of existing facilities by maintaining output and stability during grid disturbances, reducing economic losses and enhancing grid robustness.
Implementation Method 1
a photovoltaic inverter that converts direct current electricity generated by a photovoltaic power plant into alternating current electricity
Implementation Method 2
a gridforming inverter that is linked in parallel with the photovoltaic inverter to perform voltage source control on a power grid
Implementation Method 3
the switch of the DC link device is conducted (on) and the photovoltaic inverter and the gridforming inverter are connected to each other when the DC voltage of the gridforming inverter is lower than that of the photovoltaic inverter
Data Source
AI summary
The present disclosure relates to curtailment control technology for photovoltaic power generation, and more particularly, to a gridforming type curtailment control system and method in link with a photovoltaic inverter. According to the present disclosure, inertia control that cannot be performed in existing photovoltaic inverters may be performed more continuously in link with a gridforming inverter, thereby having an effect of efficiently managing and utilizing existing photovoltaic inverter facilities.