Dynamic Voltage Restorer Using Self-Service Transformer Circuitry
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Solution Overview
Problem
Voltage sags in power systems, which are sudden reductions in RMS voltage, frequently occur and can cause interruptions and malfunctions in voltage-sensitive loads, necessitating effective detection and correction to protect these loads.
Innovation Solution
A voltage fault detection system that acquires a reference voltage signal from a power line, determines a correction voltage, and applies it using shunt and series transformer circuitry to correct voltage sag conditions without requiring separate energy storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage sags are left uncorrected in the power system, then the system complexity remains low, but voltage-sensitive loads experience interruptions and malfunctions
Solution Approach 1:
The patent introduces a DVR system as an intermediary device between the power source and loads. This mediator detects voltage sags and injects correction voltages through series-connected injection transformers to restore voltage levels, protecting loads without requiring fundamental changes to the entire power system architecture
Solution Approach 2:
The DVR system uses the existing power line voltage itself as the source for generating correction voltages. By deriving correction voltages from the reference voltage signal already present in the power line, the system eliminates the need for separate energy storage devices, making the system self-sufficient and reducing overall complexity
2Reliability
If separate energy storage devices are used to generate correction voltages, then voltage sag correction capability is improved, but system complexity and cost increase
Solution Approach 1:
The system uses the power line voltage itself as the energy source for generating correction voltages. The reference voltage signal from the power line is processed through voltage transformation and inversion circuits to produce correction voltages, eliminating the need for external energy storage devices like capacitors or batteries
Solution Approach 2:
The patent changes the electrical parameters of the reference voltage signal through transformation ratios and phase shifts. By adjusting the turns ratio of injection transformers and controlling the firing angles of thyristors, the system generates correction voltages with appropriate magnitude and phase without requiring energy storage
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 effectively corrects voltage sag conditions by deriving and applying correction voltages directly from the power line, ensuring that downstream loads are not affected by voltage reductions, thus improving power quality and protecting sensitive equipment.
Implementation Method 1
shunt transformer circuitry configured to derive the correction voltage using the reference voltage signal
Implementation Method 2
series transformer circuitry configured to apply the correction voltage to the power transmission path
Data Source
AI summary
A system, in one embodiment, includes a voltage fault detection system. The voltage fault detection system may be configured to acquire a reference voltage signal from a power line to determine if a voltage sag condition is present in the power line, determine a correction voltage for correcting the voltage sag condition, use the reference voltage to produce the correction voltage, and apply the correction voltage to the power line.