Adaptive Power System Protection Against Extreme Fault Currents

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Solution Overview

Problem

Power systems face challenges in managing extreme fault currents that exceed the breaking capacity of circuit breakers, leading to prolonged fault clearing times and increased equipment outages, as the increasing demand for electric energy results in higher short circuit levels, and existing solutions like fault current limiters are expensive and require extensive maintenance.

Innovation Solution

The implementation of adaptive protection methods using International Electrotechnical Commission (IEC) 61850 communication protocols for smart cascading switching actions, which allow for the quick isolation of faulty parts of the power system through intelligent electronic devices (IEDs) without the need for fault current limiters, by determining the order of switching actions based on the location of the fault current and utilizing supervisory protection algorithms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard circuit breakers are used with breaking capacities of 40 kA or 50 kA, then the protection equipment is cost-effective and maintenance is manageable, but the fault clearing time increases and equipment outages occur when short circuit levels exceed these breaking capacities

Engineering Contradiction:

Improvefault clearing capabilityVSAvoidfault clearing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system segments the fault clearing function into two parts: standard circuit breakers handle normal fault currents up to their breaking capacity, while a controlled switching device handles extreme fault currents exceeding the breaker capacity. This segmentation allows each component to operate within its optimal range, maintaining reliability without requiring oversized breakers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A controlled switching device acts as an intermediary between the power system and standard circuit breakers. This mediator detects extreme fault currents, isolates them before they reach the breakers, and enables the breakers to clear faults within their capacity range, thereby reducing fault clearing time without requiring breakers with excessive breaking capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If fault current limiters are installed to reduce short circuit levels below circuit breaker breaking capacities, then fault clearing time is reduced and reliability is improved, but the system cost and maintenance requirements increase significantly

Engineering Contradiction:

Improveprotection against extreme fault currentsVSAvoidsystem complexity and maintenance

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of installing expensive, complex fault current limiters that require extensive maintenance, the system uses standard circuit breakers with known breaking capacities combined with a controlled switching device. This approach replaces costly protective equipment with more economical components that have simpler maintenance requirements, achieving the same reliability goal through a different technical path.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The controlled switching device automatically detects extreme fault currents and executes switching actions without requiring external intervention or complex coordination with fault current limiters. This self-service capability reduces system complexity and eliminates the need for maintenance-intensive fault current limiting equipment.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If circuit breakers with higher breaking capacities (e.g., 50 kA instead of 40 kA) are selected to handle higher short circuit levels, then the system can handle higher generation capacities, but the cost of protection equipment increases

Engineering Contradiction:

Improvehandling capacity for higher generation levelsVSAvoidcost of protection equipment

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The system dynamically adapts to varying fault current levels by using a controlled switching device that responds to actual fault conditions. This allows standard circuit breakers with fixed breaking capacities to effectively handle variable fault levels up to their capacity, while the controlled switch handles exceedances, providing adaptability to higher generation capacities without requiring breakers to be oversized for maximum possible faults.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10910835B1Systems and methods for protecting against fault currents

Publication Date: 2021.02.02 FLORIDA INTERNATIONAL UNIVERSITY

AI summary

Adaptive protection methods and systems for protecting agains) extreme fault currents in a power system are provided. Communication capabilities and protocols defined in IEC 61850 can be used to provide smart cascading switching actions for removing the fault from the power system. A supervisory protection algorithm can be used, and the protection can be activated if the fault current is higher than a breaking capacity of the circuit breakers of the power system.