Communication Network Ground Fault Detection Circuit Breakers

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Solution Overview

Problem

Existing power distribution systems face challenges in accurately detecting and responding to fault currents due to varying sensor sensitivities and tolerances, leading to unnecessary tripping of circuit breakers and potential safety hazards during maintenance, especially in systems with multiple sources and complex topologies.

Innovation Solution

The implementation of a communication network among circuit protection devices that allows for the transmission and reception of electrical current data, enabling coordinated operation and intelligent zone selective interlocking, as well as coordinated maintenance mode and ground fault detection, to accurately identify and address fault conditions without unnecessary tripping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If circuit breakers use nested current thresholds to avoid overlapping fault current thresholds, then unnecessary tripping is reduced, but fault detection accuracy deteriorates due to varying sensor sensitivities and tolerances

Engineering Contradiction:

Improvecircuit breaker operation reliabilityVSAvoidfault current detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent combines current measurements from multiple circuit breakers (both upstream and downstream) to collectively determine ground fault conditions. By merging data from multiple sensors with different sensitivities and tolerances, the system achieves more accurate fault detection than any single breaker could provide, while maintaining reliable operation through coordinated decision-making.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If circuit breakers use dedicated blocking signal connections for coordination, then coordination reliability is improved, but system complexity increases

Engineering Contradiction:

Improvecoordination reliabilityVSAvoidsignal connection complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the communication network universal by using it for multiple purposes: ground fault detection, blocking signal transmission, and general coordination communication. This multi-functional approach eliminates the need for separate dedicated blocking signal connections, reducing system complexity while maintaining coordination reliability through the same robust network infrastructure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If ties send blocking signals to all connected sources, then safety is improved, but productivity deteriorates due to unnecessary blocking of all sources

Engineering Contradiction:

Improvesystem safetyVSAvoidpower distribution efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by enabling each circuit breaker to independently evaluate ground fault conditions based on its own current measurements and the measurements of other breakers. This localized decision-making allows ties to selectively block only the specific source or feeder where a ground fault is detected, rather than unnecessarily blocking all connected sources, thus maintaining both safety and productivity.

Inventive Principle:

Principle #3Local quality

4Device complexity

If circuit breakers operate independently without communication network, then device complexity is reduced, but information sharing capability deteriorates

Engineering Contradiction:

Improvesystem complexityVSAvoidcurrent measurement information sharing

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent introduces a communication network as an intermediary that facilitates information sharing between circuit breakers without requiring complex direct connections between each pair of breakers. The network acts as a mediator that collects, transmits, and distributes current measurement information, enabling coordinated ground fault detection while keeping individual breaker complexity low and maintaining standardized communication protocols.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10797479B2Power distribution systems and methods of performing ground fault detection in power distribution systems with a communication network

Publication Date: 2020.10.06 ABB SPA

AI summary

A method of operating an electrical power distribution system including a plurality of circuit protection devices and an additional circuit protection device communicatively coupled by a communications network is described. The method includes transmitting, by each circuit protection device of the plurality of circuit protection devices, an electrical current communication to the communication network, the electrical current communication including an indication of an electrical current detected by the transmitting circuit protection device formatted according to a network communication protocol of the communication network. The additional circuit protection device receives the electrical current communications from the plurality of circuit protection devices and determines, based on the received electrical current communications, whether a ground fault condition exists in the electrical power distribution system.