Power Factor Sensing Circuit for Reactive Load Compensation
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Solution Overview
Problem
In subsea oil and gas applications, the inefficiency of Alternating Current (AC) power transmission due to capacitive and inductive loads results in a sub-unity power factor, leading to increased energy costs and equipment over-specification, as reactive power is wasted and requires complex analysis for load adjustments.
Innovation Solution
A method and apparatus that utilize feedback elements to monitor and control the phase difference between voltage and current, selectively connecting capacitive or inductive elements to maintain a power factor close to unity, employing a sensing circuit with inductive and capacitive feedback, and a control unit for real-time adjustments to manage reactive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If AC power is transmitted through umbilical cables to subsea loads, then electrical power can be delivered to remote locations, but the capacitive nature of the cables causes poor power factor and reduced transmission efficiency
Solution Approach 1:
The patent converts the harmful capacitive effect of the umbilical cable into a beneficial element by adding inductive reactors that counterbalance the cable's capacitance. This transforms the power factor correction from a problem-solving measure into a system-integrated solution, improving transmission efficiency while utilizing the existing cable characteristics
Solution Approach 2:
The system dynamically adjusts the reactance values of the reactors to optimize power factor under varying load conditions. By changing the electrical parameters (reactance) in response to system conditions, the patent maintains efficient power transmission across different operating scenarios
2Measurement precision
If complex electrical analysis is performed to determine necessary power increases when adding loads, then accurate power system design is achieved, but system complexity and analysis time increase significantly
Solution Approach 1:
The patent implements self-service through automated power factor correction where the control system continuously monitors system conditions and automatically adjusts reactor configurations. This eliminates the need for complex manual electrical analysis when adding loads, as the system self-optimizes to maintain desired power factor and capacity
Solution Approach 2:
The system incorporates feedback mechanisms that monitor power factor, load conditions, and system performance in real-time. This feedback enables automatic adjustment of power factor correction elements, providing accurate power management without requiring complex external analysis or intervention
3Adaptability or versatility
If reactive power is provided to establish electric and magnetic fields in the AC system, then capacitive and inductive loads can operate, but the reactive power does not contribute to useful work and increases apparent power requirements
Solution Approach 1:
The patent applies the counterweight principle by introducing inductive reactors to counterbalance the capacitive effects of the umbilical cable and capacitive loads. This neutralizes the reactive power oscillations, allowing the system to handle diverse loads while minimizing the total apparent power requirement and improving overall system efficiency
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
This solution enables efficient power delivery by maintaining a power factor within a desired range, reducing energy waste and the need for over-specification, and allows for automatic compensation without complex analysis, enhancing the reliability and efficiency of subsea power systems.
Implementation Method 1
at least one first feedback element for coupling to a power line that delivers electrical power from an Alternating Current (AC) source to a load and for providing a first feedback voltage that represents a voltage provided by the power line; at least one further feedback element for coupling to the power line for providing a further feedback voltage that represents a current provided by the power line
Implementation Method 2
at least one impedance element, having an electrical impedance, wherein a first potential difference across the impedance element that is responsive to a potential difference between the first feedback voltage and the further feedback voltage, indicates a characteristic associated with a power factor for the power line
Data Source
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AI summary
A method and apparatus are disclosed for indicating one or more characteristics associated with a power factor for a power line. The apparatus includes at least one feedback element for coupling to a power line that delivers electrical power from an Alternating Current (AC) source to a load and for providing a first feedback voltage that represents a voltage provided by the power line; at least one further feedback element for coupling to the power line for providing a further feedback voltage that represents a current provided by the power line; and at least one impedance element, having an electrical impedance, wherein a first potential difference across the impedance element that is responsive to a potential difference between the first feedback voltage and the further feedback voltage, indicates a characteristic associated with a power factor for the power line.