Impedance Determination in Electrical Networks Without Phase Data
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Solution Overview
Problem
Existing methods for determining the impedance of an electrical power network are complex and require continuous updating, disrupting normal system operation, especially when modifications are made to the energy grid, and often involve active parameter changes that can disrupt normal operation.
Innovation Solution
A computer-assisted method that measures electrical voltage, active power, and reactive power at a connection point, using specific criteria to determine impedance values independently of voltage phase, with threshold-based conditions to ensure accuracy and minimize estimation errors, allowing for accurate impedance determination in inductive networks with small or no real impedance part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If computer modeling of electrical components is used to calculate impedance, then impedance can be determined, but the method becomes complex and requires continuous updating when grid modifications are made
Solution Approach 1:
The patent replaces complex computer modeling of electrical components with a simplified measurement-based calculation method. Instead of modeling the entire network topology and component properties, the invention uses direct measurements of voltage and reactive power at the connection point to calculate impedance through a mathematical relationship, eliminating the need for complex simulations and continuous model updates.
Solution Approach 2:
The system determines impedance using measurements taken during normal operation at the connection point itself, without requiring external testing equipment or complex network-wide measurements. The method uses locally available voltage and reactive power data to self-determine the impedance parameter.
2Measurement precision
If active parameter changes are made to determine grid properties, then impedance can be measured, but normal system operation is disrupted
Solution Approach 1:
The patent enables impedance determination during continuous normal operation of the power generation system. By using measurements of voltage and reactive power that are already available during regular operation, the method eliminates the need to interrupt service or actively perturb the system, allowing impedance to be determined without disrupting the continuous useful action of power generation and delivery.
3Measurement precision
If impedance is determined using traditional methods, then impedance values can be obtained, but frequent updates are required when energy grid modifications are made
Solution Approach 1:
The patent replaces time-consuming computer modeling and simulation processes with an immediate calculation method based on current measurements. When grid modifications occur, the system simply performs new voltage and reactive power measurements and calculates the updated impedance value instantly through the established mathematical relationship, eliminating the need for time-intensive model reconstruction and validation.
Data Source
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AI summary
The invention relates to a method for the computer-aided ascertainment of the impedance of an electrical energy network (EN), wherein the electrical voltage (VPCC), the active power (PPCc) and the reactive power (QPCC) are measured at a connection point (PCC), by which an electrical energy production installation is connected to the energy network (EN), at respective successive instants. In this case, the impedance value (ZGE) is estimated at respective present instants by means of a computation code that is independent of the phase of the measured voltage (VPCC). The estimation is carried out only for relatively large variations in the measured voltage or reactive power. The estimate is also taken into account only if its estimate error is small. The invention is based on the insight that accurate estimation of the impedance is possible at particular operating points of the energy network even without knowledge of voltage phase. The method according to the invention is used particularly in an energy network to which a wind turbine or a wind farm comprising multiple wind turbines is connected.