by Alex Apostolov, Editor-in-Chief

The Changing World of Generator Protection

In August 2003 we experienced one of the worst blackouts in North American history. After almost an hour of different events weakening the electric power system, finally an impedance relay with mho characteristic tripped a 345 kV line due to load encroachment, thus delivering the final drop that triggered the collapse of the NE power grid.

As a result more than 50 million people in the US and Canada lost power in an event with an estimated price tag of around 6 billion US dollars.
While the blackout took about an hour to develop, it took a few months to analyze. It was a process that involved many experts, working to get the data from multiple devices and to convert it into a common format that can be processed in order to understand the sequence of events during the disturbance.
Their task was further complicated by the fact that many of the protection devices were electromechanical and did not have the ability to record what made them mis-operate, while at the same time the ones that were microprocessor based and did have disturbance and event recording capabilities were not always properly time-synchronized.

The experience from this blackout triggered several activities with the goal to help the industry with the analysis of blackouts in the future. Since it was clear that one of the biggest challenges was the proprietary format of the event reports and setting files available from the multifunctional protection IEDs that operated during the wide area disturbance, the IEEE Power and Energy Society Power System Relaying Committee started three new working groups with the goal to define common formats for settings files, events and disturbance records that can be processed by automated disturbance analysis tools. Based on the experience from the development of IEC 61850, its object models, services and the substation configuration language files, the idea was to define XML based file formats using the standard definitions. This would then allow any suppliers’ tools to import or export setting, event or disturbance files in a common format that can be used by any disturbance analysis or engineering software.

All three working groups (WG) have completed their tasks.

  • WG H5a published a report on Common Format for IED Configuration Data that will serve as the starting point for the development of the standard XML based settings file format
  • WG H5b’s work resulted in the publishing of IEEE C37.239 Standard for Common Format for Event Data Exchange (COMFEDE) for Power Systems, based on XML
  • WG H5c published a report on the relationship of IEC61850 and COMTRADE

At the same time CIGRE B5 launched a working group with the task to report on the new trends for automated fault and disturbance analysis. The report of this working group was published as CIGRE brochure 424.

When we started working on the development of the PAC World magazine concept in 2006 and were considering the different types of articles to be included in each of its issues, one of the first to agree on was the Blackout watch. It is essential for our industry to learn from our experience and the experience of others. That is why we not only include a short description of disturbances that occurred during the three months between the issues of the magazine, but also try to include short articles providing some details and reference information related to major disturbance.

We believe that this can help in limiting or even avoiding some blackouts in the future. But to achieve this goal we need the help of our community, because in many cases it is very difficult to find detailed information on the sequence of events that resulted in the system collapse.
By working together on understanding the anatomy of blackouts, and the development of standards based tools for automated disturbance analysis, we can bring this field in line with the smart technologies of the 21st century.
“Coming together is a beginning;
keeping together is progress; working together is success.”

Henry Ford


Relion advanced protection & control.
BeijingSifang June 2016