Voltage-Source Converter Control for Mesh Grid Voltage and Loss Management
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Solution Overview
Problem
Existing electrical power distribution networks face challenges with high penetration of distributed generators, leading to power flow exceeding thermal limits, cable insulation failure, transformer damage, and voltage violations, with inadequate reactive power regulation and active-reactive closed loop control for voltage source converters.
Innovation Solution
A voltage-source converter (VSC) with a controller that uses pulse-width-modulated signals to manage active and reactive power flow, maintaining target AC voltage by absorbing or injecting reactive power, and a pi-equivalent circuit model to minimize power losses through optimal setting of active and reactive power values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high penetration of distributed generators is introduced to supply power directly to distribution networks, then the amount of power supplied to consumers is improved, but power flow exceeds thermal limits causing cable insulation failure, transformer damage, and voltage violations
Solution Approach 1:
The patent changes the operating parameters of the distribution network by introducing a voltage-source converter that dynamically adjusts reactive power injection/absorption. This allows the system to maintain voltage within acceptable limits and prevent thermal overload while accommodating high DG penetration, thus resolving the contradiction between increased power supply capacity and network safety
Solution Approach 2:
The voltage-source converter acts as an intermediary device between the distributed generators and the distribution network. It provides local reactive power support and active power control to manage power flow, preventing thermal limits exceedance and voltage violations while enabling high DG penetration
2Device complexity
If reactive power regulation is not incorporated into AVC strategy, then the control system complexity is reduced, but effective active and reactive closed loop control is absent leading to voltage violations
Solution Approach 1:
The patent merges active power control and reactive power regulation into a unified voltage-source converter control system. The controller simultaneously manages both active and reactive power flows based on voltage measurements, creating an integrated closed-loop control that ensures voltage stability without requiring separate complex control systems
Solution Approach 2:
The voltage-source converter is designed with multi-functionality, serving both as an active power transfer device and a reactive power compensation device. This universal device performs multiple functions (active power control, reactive power regulation, voltage support) that would traditionally require separate systems, maintaining voltage stability while avoiding excessive complexity
3Productivity
If power flow is increased to meet high demand, then the productivity is improved, but thermal limits of cables and overhead lines are exceeded causing insulation failure and equipment damage
Solution Approach 1:
The patent changes the power flow parameters by introducing controlled reactive power injection/absorption at strategic points in the distribution network. This allows increased active power delivery to meet high demand while the reactive power control maintains voltage levels that prevent thermal overload and insulation failure
Data Source
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AI summary
A method of controlling an electricity distribution network, wherein the electricity distribution network is a mesh network including a plurality of loads and there is a voltage- source converter connected to a point in the network. The method comprises, while using the voltage-source converter to try to hold the voltage magnitude constant at said point, establishing a record of how, at said point, the real power flowing between the network and the voltage-source converter varies with variation of the reactive power that the voltage-source converter causes to flow between itself and the network, using a reactive- power value, proportional to the sum of the reactive-power draws of the loads, in order to look up a real-power value from the record, and configuring the voltage-source converter to supply into the network at said point reactive and real power at said reactive- and real- power values, respectively.