Voltage State Determination in Low Voltage Distribution Networks

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Solution Overview

Problem

Current voltage regulation techniques in electricity distribution networks, particularly with the integration of decentralized renewable energy sources, struggle to maintain voltage within regulatory ranges due to significant fluctuations, which cannot be effectively managed under economic conditions.

Innovation Solution

A method using computer-based systems to determine the voltage state of low voltage branches by constructing and solving Kirchhoff equations, formulating active and reactive powers as quadratic functions, and applying iterative minimization and successive linearization methods to achieve precise voltage regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If decentralized renewable energy generators are connected to the distribution network, then energy production is improved and transport costs are reduced, but voltage fluctuations occur that exceed regulatory ranges

Engineering Contradiction:
Improvedecentralized energy productionVSAvoidvoltage within regulatory ranges
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by continuously measuring actual voltages at network nodes and comparing them against target voltage values. Based on this comparison, the system automatically adjusts transformer ratios to correct voltage deviations, ensuring voltage remains within regulatory ranges despite fluctuations from decentralized generators.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the transformation ratio parameter of transformers based on measured voltage conditions. By adjusting this parameter in response to voltage fluctuations from renewable energy generators, the system maintains voltage within acceptable ranges while accommodating decentralized power production.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If local voltage measurement and fixed setpoint regulation is used, then voltage control is simple, but it cannot effectively manage voltage fluctuations from multiple decentralized generators

Engineering Contradiction:
Improvevoltage regulation simplicityVSAvoidvoltage regulation effectiveness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent transitions from static fixed setpoint regulation to dynamic adaptive regulation. The system continuously updates target voltage values based on actual measurements and adjusts transformer ratios in real-time, enabling effective management of voltage fluctuations from multiple decentralized generators while maintaining operational simplicity through automated control.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If conventional voltage regulation techniques are applied, then implementation is straightforward, but computational resources are insufficient for precise voltage state determination

Engineering Contradiction:
Improveregulation implementation easeVSAvoidvoltage state determination accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary computational layer that uses measured voltages and power flows to calculate voltage states at unmeasured nodes through Kirchhoff equations and optimization algorithms. This intermediary calculation system achieves precise voltage state determination across the entire network without requiring direct measurement at every node, balancing implementation feasibility with measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3598598B1Method and system for determining a voltage state of a low voltage power supply network located at at least one transformer station
Publication Date: 2021.04.14 ELECTRICITE DE FRANCE
  • EP3598598B1 patent drawingFigure 1~2
  • EP3598598B1 patent drawingFigure 3
  • EP3598598B1 patent drawing

AI summary

A method for determining a voltage state of a low voltage distribution network at the level of at least one transformer station (TRANSF), the low voltage (LV) branch comprising a plurality of nodes, includes: - a definition (S5) of a value of an actual target voltage and an estimation (S2) of an active power and a reactive power for each node;- a construction (S1) of a first system of equations linking complex voltages to the active and reactive powers of the plurality of nodes, - a respective formulation (S3) of the active and reactive powers in the form of a quadratic function for each node to obtain a second system of equations, - a determination (S4) of an auxiliary function from the second system of equations, - an iterative minimization (S6) of the auxiliary function until a solution is obtained in the vicinity of an approximate global minimum of the auxiliary function, - and an application to the second system of equations of an iterative method by successive linearizations (S7), having as an initial solution at the first iteration the approximate global minimum, until a value of a complex voltage is obtained at each node.;