Mar 2013
Electricity Transmission
Design of a Smart Tool for Detecting Hidden Errors in Protection Setting Files
Mar 2013
National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
Gas Distribution Networks
Relying solely on people and procedures to assess the validity of protection relay setting files has not always been successful and occasionally hidden errors were not detected until after a relay mal-operated. In addition, a mal-operation related to an inappropriate setting may only become apparent when the power system is operating in a stressed or abnormal state and consequently might cause a local black-out or trigger a regional collapse.

Setting errors, or hidden problems in the setting files used in protection relays, have resulted in mal-operations. This project will investigate a method based on an expert system that will detect hidden errors in a setting file.

This project will deliver an intelligent tool (a computer software application or expert system) which can open a setting file and interrogate the protection functions and settings in the file. Knowledge-based rules and/or cases (and possibly other knowledge-representation methods) will be extracted and these will be deployed within an intelligent system in order to ascertain that no settings are erroneous. This includes checks that relay settings are correct and that no features are inadvertently enabled or disabled.

The knowledge used to assess the validity of settings will be derived from NG protection application/settings policy documents and also (possibly) from structured knowledge elicitation interviews conducted with expert personnel from the company.

A simple power system model will be used by the tool to test the settings to validate that they are correct and to provide a further means of checking for hidden errors by applying various in-zone and out-zone faults on the power system model.