Power Flow Calculation Using Feeder Power Factor Angles
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Solution Overview
Problem
Real-time power flow measurements in electrical distribution systems are limited due to the lack of real-time data from individual customer meters, complicating dynamic resource allocation and making offline power flow models less effective for determining real-time power flows.
Innovation Solution
A load scaling method that calculates accurate real-time power flow by determining power factor angles and scaling factors using measured current and injected power data, allowing for improved estimation of power usage across feeders in distribution networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If offline power flow modeling is used in distribution systems, then modeling simplicity is improved, but real-time resource allocation capability deteriorates
Solution Approach 1:
The patent transforms the power flow problem from a complex differential equation system into an algebraic equation system by assuming constant voltage magnitudes and using power factor angles as key parameters. This parameter transformation simplifies the modeling while enabling real-time computation for dynamic resource allocation.
Solution Approach 2:
The patent applies different modeling approaches to different parts of the distribution system. At the substation level, it uses measured real-time data (currents, power factors), while at the load level, it uses historical consumption patterns. This localized approach balances modeling accuracy with computational simplicity.
2Measurement precision
If real-time power flow measurement is implemented at all loads, then measurement accuracy is improved, but system cost and complexity deteriorates
Solution Approach 1:
The patent introduces power factor meters as intermediary measurement devices at load points, which are simpler and cheaper than full power flow measurement systems. These devices provide sufficient information (power factor and current) to enable accurate power flow estimation when combined with historical data, avoiding the need for complex measurement systems at every load point.
Solution Approach 2:
The patent creates a virtual model of the distribution system that replicates real-time power flow conditions using measured data from critical points (substations, feeders) combined with historical load patterns. This virtual copy provides accurate power flow information without requiring physical measurement devices at every location.
3Loss of information
If historical consumption data is used to estimate real-time power usage, then data availability is improved, but measurement accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where historical consumption patterns are continuously updated with actual measured data from power factor meters and substation measurements. This feedback loop allows the system to learn and adapt to changing load behaviors, maintaining accuracy while utilizing the advantages of historical data.
Solution Approach 2:
The patent transforms static historical consumption data into dynamic real-time estimates by combining it with current measurements of power factors and currents. The system dynamically adjusts power flow estimates based on real-time conditions while leveraging historical patterns, making the estimation both accurate and timely.
Data Source
AI summary
A method for determining a power flow in an electrical distribution network (104) includes determining respective feeder apparent powers of electrical power feeders (114) connected at a supply node (118) of the electrical distribution network. The method also includes determining a feeder power factor angle of at least one of the feeders responsive to the feeder apparent powers, a supply node active power, and a supply node reactive power. The method then includes using at least one of the feeder power factor angles for determining a power flow in the electrical distribution network, such as by calculating feeder active and reactive power and using these powers to provide load allocation.