Grid Power Support Switching for Inertia and Short-Circuit Strength
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Solution Overview
Problem
Power grids face challenges in maintaining frequency stability and short circuit level due to reduced inertia and increased penetration of non-synchronous generation, requiring more flexible and efficient support from grid devices.
Innovation Solution
A power supporting arrangement comprising voltage source converters, synchronous machines, and switching arrangements that allow for flexible connection modes to provide reactive power and inertia support, enabling efficient use of a limited number of devices across various operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a synchronous machine is directly connected to the power grid via a transformer, then the connection is simple and reliable, but the flexibility in providing different types of power support is limited
Solution Approach 1:
The switching arrangement is designed with multiple positions that enable a single synchronous machine to perform multiple functions: direct grid connection for simple support, connection via converter for advanced support, and bypass options. This multi-functional switching arrangement resolves the contradiction by providing adaptability without requiring separate dedicated systems for each support mode.
Solution Approach 2:
The switching arrangement dynamically changes the connection topology between the synchronous machine and the power grid based on operational requirements. The ability to switch between different connection modes (direct, via converter, bypass) allows the system to adapt its complexity level according to the specific power support needs, resolving the contradiction between flexibility and complexity.
2Reliability
If multiple grid supporting devices are used to provide comprehensive power support, then the power support capability is enhanced, but the number of devices increases and system complexity increases
Solution Approach 1:
A single synchronous machine equipped with a multi-position switching arrangement can replace multiple dedicated supporting devices. The machine can operate in different modes (direct connection, converter connection, bypass) to provide various types of power support, thereby achieving comprehensive support capability with fewer devices and reduced system complexity.
Solution Approach 2:
The invention merges the functions of multiple grid supporting devices into a single synchronous machine system. By combining direct connection capability, converter connection capability, and bypass functionality into one integrated system, the patent achieves enhanced power support capability without proportionally increasing the number of devices.
3Adaptability or versatility
If a synchronous machine is connected via a power converter, then the control flexibility and power support options are increased, but the device complexity and cost increase
Solution Approach 1:
The switching arrangement dynamically selects whether to connect the synchronous machine directly to the grid or through the power converter based on the required power support mode. This dynamic switching capability allows the system to use the converter only when advanced power support options are needed, rather than permanently increasing complexity, thus resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The connection structure is segmented into multiple paths: a direct connection path, a converter connection path, and bypass options. The switching arrangement selectively activates the appropriate path based on operational requirements, allowing the system to incorporate the converter's advanced capabilities without always incurring its complexity overhead.
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 solution increases flexibility in connecting grid support devices, allowing them to be used in more versatile and efficient operational modes, enhancing frequency stability and short circuit level support, thereby maximizing the utilization of existing grid support components.
Implementation Method 1
a first voltage source converter having an AC side and a DC side, a second voltage source converter having an AC side and a DC side
Data Source
AI summary
A power supporting arrangement for a power grid includes a first and a second voltage source converter with an AC side and a DC side. A DC link interconnects the DC sides of the voltage source converters. A first switching arrangement includes a number of settable positions. The AC side of the second voltage source converter is connected to the power grid and the first switching arrangement is connected between a first synchronous machine. The AC side of the first voltage source converter and the power grid and operable to selectively connect the first synchronous machine to the power grid or to the AC side of the first voltage source converter.