Time Offset Determination for Electrical Line Synchronization

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Solution Overview

Problem

Existing methods for determining time offset between measuring devices on electrical lines, such as those used in differential protection, face challenges like satellite connection failures and high costs associated with synchronized clock systems, leading to inaccuracies and system failures.

Innovation Solution

A method that minimizes a cost function based on a mesh equation to determine phase differences between measuring pointers, allowing for precise synchronization of measuring devices by calculating line-related and measuring device-related phase differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If GPS signals are used to synchronize measuring devices, then time offset determination is enabled, but the system becomes vulnerable to satellite connection failures

Engineering Contradiction:

Improvereliability of time offset determinationVSAvoidsatellite connection failure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary method using mesh equations and cost function minimization to determine time offsets between measuring devices. Instead of directly relying on GPS signals, the system uses electrical measurements and mathematical optimization as an intermediary mechanism to achieve synchronization, thereby eliminating vulnerability to satellite failures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The measuring devices perform self-synchronization by autonomously determining time offsets through local measurements and cost function minimization. Each device uses its own measurements and the mesh equation to calculate the optimal time offset, enabling the system to serve itself without external GPS dependency.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If special IP network components with synchronous clock are used, then time offset determination accuracy is improved, but the system cost increases significantly

Engineering Contradiction:

Improvetime offset determination accuracyVSAvoidsystem cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive specialized IP network components with standard, inexpensive measuring devices that can determine time offsets through mathematical optimization. The solution uses readily available equipment combined with algorithmic processing, eliminating the need for costly dedicated synchronization hardware.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes the mechanical/electrical synchronization system (specialized clock components) with a computational approach using cost function minimization. Instead of relying on physical synchronization hardware, the system uses mathematical optimization based on electrical measurements to achieve the same synchronization effect.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If standard measuring devices are used without specialized synchronization components, then system cost is reduced, but time offset determination accuracy deteriorates

Engineering Contradiction:

Improvesystem costVSAvoidtime offset determination accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the approach from hardware-based synchronization to parameter-based optimization. By minimizing a cost function that depends on time offset parameters, the system achieves high measurement precision using standard devices. The optimization process transforms the problem from one requiring specialized hardware to one solvable through mathematical parameter adjustment.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the need for specialized synchronization hardware with a computational method using cost function minimization. Standard measuring devices combined with mathematical optimization achieve the same precision as expensive specialized systems, substituting mechanical/electrical complexity with algorithmic simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3355432B1Method for determining a time offset between measured values

Publication Date: 2021.07.14 SIEMENS AG

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AI summary

The invention relates, inter alia, to a method for determining a time offset measurement value, which indicates the time offset between a first measurement value, acquired with a measuring device (21) arranged at a first location (11) of an electrical line (10) or an electrical network, and at least a second measurement value, acquired with at least one measuring device (22) arranged at a second location (12) of the electrical line (10) or the electrical network. According to the invention, a first measuring pointer (UA) is determined as the first measurement value and a second measuring pointer (UB) as the second measurement value, using the first and second measuring points to measure the line section or the electrical network.The line model describes a line-related phase difference value between the first and second position (11, 12), which describes the line-related phase offset (ϕU,AB) between the first and second measuring pointer in synchronous measuring point measurement, and a measuring device-related phase difference value (ϕF), which is based on a time offset between the measuring points in the case of asynchronous measuring point determination of the measuring devices (21, 22), and the time offset measurement value is formed solely by the measuring device-related phase difference value (ϕF) or by taking into account the measuring device-related phase difference value (ϕF).