Primary-Side Voltage Estimation for Utility Power Regulation
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Solution Overview
Problem
Traditional utility power grid voltage regulation systems rely on physical measurements, which are costly, prone to inaccuracies due to long distance cabling, and pose safety risks, and lack effective backup methods during failures.
Innovation Solution
A method and system for regulating utility power that estimates the primary-side line voltage signal using secondary-side voltage, load feeder-line current, and regulator-line current signals, allowing for voltage and power factor regulation without direct measurement of the primary-side voltage, utilizing a power converter and voltage estimation circuit to generate and regulate AC voltage, power factor, or reactive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical voltage measurements are used with potential transformers, then voltage regulation accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent creates an electrical copy of the primary-side voltage signal by transforming the secondary-side voltage measurement through the complex conjugate of the transformer turns ratio. This electrical copy allows the system to use the cheaper secondary-side measurements while achieving primary-side voltage regulation accuracy, eliminating the need for expensive potential transformers on the primary side.
Solution Approach 2:
The patent introduces an intermediary mathematical transformation process that converts secondary-side voltage measurements into an equivalent primary-side voltage representation. This intermediary approach allows indirect measurement of primary voltage through secondary measurements combined with transformer parameters, avoiding direct primary-side voltage sensing.
2Reliability
If physical voltage measurements are used at the primary side, then voltage regulation is improved, but safety risks increase
Solution Approach 1:
The patent uses the transformer as an intermediary device that electrically isolates the measurement system from the high-voltage primary side. By performing measurements on the secondary side and mathematically transforming the results, the system achieves primary-side voltage regulation without placing sensors in the dangerous high-voltage environment where arc flash hazards exist.
Solution Approach 2:
The patent creates a safe electrical copy of the primary voltage signal on the secondary side through mathematical transformation. This copy allows operators to work with voltage regulation while remaining on the safer secondary side, eliminating direct exposure to primary-side arc flash hazards.
3Area of stationary object
If long distance cabling is used for voltage measurement, then measurement coverage is improved, but measurement accuracy deteriorates
Solution Approach 1:
The patent places the voltage measurement sensor on the secondary side where short cabling can be used, and uses the transformer as an intermediary to extend the effective measurement coverage to the primary side. This approach maintains measurement accuracy by avoiding long primary-side cables while still achieving primary-side voltage regulation.
Data Source
AI summary
A utility power regulation system includes a power converter configured to regulate one or more of a voltage and a power factor at the primary side of a step-up transformer, or at a load electrically connected to a load feeder line, based on an estimated primary-side line voltage signal. The system includes a voltage estimation circuit configured to estimate the primary-side line voltage signal from one or more signals received from a secondary-side voltage sensor, regulator line current signal, and a primary-side load feeder-line current sensor.