Active Distribution Network Voltage Control Across Multiple Time Scales
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Solution Overview
Problem
The integration of distributed power supplies into distribution networks leads to voltage fluctuations, flickers, and sags, compromising network stability and efficiency, necessitating improved voltage control methods.
Innovation Solution
A multi-time scale voltage control method that calculates reactive power sensitivity, determines capacitor bank configuration, and optimizes power outputs to maintain voltage within a safe range, using DQN and DDPG algorithms for real-time adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed power supplies are accessed to distribution networks, then power supply safety and reliability are improved, but voltage fluctuations and flickers occur causing voltage violations
Solution Approach 1:
The patent segments the voltage control function into multiple time scales (long-term and short-term) and multiple control layers (centralized and distributed). The long-term control handles slow voltage changes through capacitor bank switching, while the short-term control addresses rapid fluctuations through inverter reactive power adjustment, resolving the contradiction by addressing different voltage instability mechanisms at appropriate time scales.
Solution Approach 2:
The patent implements dynamic voltage control by continuously adjusting the reactive power output of distributed inverters based on real-time voltage measurements. The control system dynamically modifies the reactive power injection to counteract voltage fluctuations caused by distributed power supply variations, transforming the static grid into a dynamically responsive system that actively compensates for voltage instability.
2Reliability
If reactive control devices such as capacitor banks are installed, then voltage control capability is improved, but device complexity and investment costs increase
Solution Approach 1:
The patent enables distributed inverters to perform multiple functions: they generate active power from distributed energy resources and simultaneously provide reactive power for voltage control. This multi-functionality eliminates the need for separate dedicated voltage control devices in many cases, reducing overall system complexity and investment costs while maintaining voltage control capability.
Solution Approach 2:
The patent implements self-service voltage control where the distributed energy resources themselves participate in voltage regulation by adjusting their reactive power output. The inverters autonomously respond to voltage deviations and adjust their operation to maintain voltage within acceptable ranges, eliminating the need for external control devices and reducing system complexity.
3Loss of energy
If existing network structure is maintained without changes, then infrastructure investment is reduced, but voltage violation problems worsen under high distributed power supply infiltration
Solution Approach 1:
The patent changes the operational parameters of existing distributed inverters by enabling dynamic reactive power adjustment capabilities. Instead of modifying the physical network structure, the solution modifies the operating characteristics of existing devices, allowing them to inject or absorb reactive power as needed to maintain voltage levels, thereby solving voltage violation problems without infrastructure changes.
Solution Approach 2:
The patent implements feedback-based voltage control where voltage measurements are continuously monitored and used to adjust the reactive power output of distributed inverters. The control system measures voltage deviations and feeds this information back to the inverters, which then adjust their reactive power injection to counteract the deviations, creating a closed-loop control system that maintains voltage stability without network modifications.
Data Source
AI summary
A multi-time scale voltage control method for an active distribution network is provided. The method comprises: establishing a voltage optimization approach taking into account a large scale of distributed power supplies to realize cooperative dynamic control in case of a voltage violation generated when the distributed power supplies are incorporated into a distribution network; under a long time scale, establishing a voltage control model for controlling a capacitor bank based on voltage sensitivity analysis to realize drastic voltage regulation in case of the voltage violation by means of reactive power compensation; and under a short time scale, establishing a distributed voltage control model, and considering the problem of voltage violation, solving an optimal control strategy online by fully using active and reactive power outputs of the distributed power supplies to realize quick voltage regulation.