See the unseen: Power data diagnostics

Using reports from relay events can help diagnose power system problems, increase system reliability, lower maintenance costs, and reduce potential for system damage and outages. Today's microprocessor-based relays collect and save event reports during faults and other problematic conditions. The event report and sequential events recorder (SER) capability of advanced relays enable protection e...

06/01/2008


Using reports from relay events can help diagnose power system problems, increase system reliability, lower maintenance costs, and reduce potential for system damage and outages.

Today's microprocessor-based relays collect and save event reports during faults and other problematic conditions. The event report and sequential events recorder (SER) capability of advanced relays enable protection engineers to gain a better understanding of faults and disturbances on transmission line systems through analysis of event reports. This analysis frequently leads to better line parameters, more accurate fault locating for complex faults, and improved understanding of electric power system operations.

Event reports help determine fault resistance and explain otherwise inexplicable events (see graph). They also aid in testing and troubleshooting relay settings and protection schemes that protect costly equipment critical to consumer and industrial services.

Event record detective

The importance of event report records was demonstrated at the city of Conway, AR, 20 miles north of Little Rock. Conway's city-owned power system includes two feeders from its substation, one supplying an industrial customer, and the other supplying the balance of the small city's business and residential customers. Technology from Schweitzer Engineering Laboratories Inc. (SEL) of Pullman, WA, helped detect what might have become a much larger problem.

“The industrial customer had detected what they considered a voltage problem,” says Emery Perry, an SEL field application technician called in to consult on the situation. “Yet when technicians from the Conway Electric Department went to inspect the substation, they noticed that there was no trip on the breaker,” Perry says. The technicians at Conway Electric received training on SEL equipment, enabling them to take advantage of event report records in the SEL relays. In the next step, technicians decided to check the event history in the SEL relays to check for relevant event reports on the feeder in question.

They found that existing event reports seemed to indicate a voltage issue. So they consulted Perry to confirm what seemed to be an unusual problem.

“From the oscillograph readings, it appeared that the problem could be in the source—and in this case the source was a transformer,” Perry says.

Hardware, software involved

Conway Electric Department uses SEL-351S-7 and SEL-351S-6 protection and breaker control relays and SEL-551 overcurrent/reclosing relays in its distribution substations. SEL-351S-7 Relay is used on the feeder main, with the SEL-551 as backup. SEL-351S-6 Relays provide feeder protection and reclosing.

Perry says event records there showed a decrease in C-phase current (IC) and C-phase voltage (VC), while A-phase and B-phase currents increased. “This occurred on two feeders. I suggested testing their transformer, which was a tap changer. When we inspected it, the rotary tap changer contacts were severely worn. [See photo.]

“What was causing the problem was that the C-phase on the utility transformer was opening up, and the industrial customer was in single phase,” Perry says. “It wasn't a complete opening; actually, the moving contacts in the transformer were arcing. That's why the event report oscillograph showed the collapsed C-phase voltage and the collapsed C-phase current, just as if you were removing the voltage off of the load C-phase. There was a three-phase system within the industrial facility that was actually single phasing, which could cause equipment damage. And, of course, the arcing of the transformer caused damage to the contacts.” Although transformers are generally among the most dependable components in an electrical system (failure rates are estimated at a minimal 76 failures per 10,000 years of transformer life), when failures occur, they can result in costly outages, considerable downtime, and expensive replacements, he explains.

Damage avoided

“In this case, I would say that early analyses of the event record helped prevent a possible transformer fire and a sustained power outage, and also possible damage to the industrial plant equipment from a continued single-phasing condition,” Perry says. Each time an SEL relay generates a standard event report, it also generates a corresponding event summary. Event description includes relay/terminal identification; event type, date, and time; fault location; and other information. Event summaries can be viewed using the front-panel LCD or front-panel serial port of the SEL-351S.

Date and time of each transition are available in event reports, downloadable to any PC, he says. The chronology helps technicians determine the order and cause of events so that comprehensive troubleshooting is facilitated. With an appropriate setting, the relay will automatically send an event summary in ASCII text to one or more serial ports each time an event report is triggered.

In addition to storing event summaries and full-length event reports, SEL relays can track the pickup and dropout of protection elements, control inputs, and contact outputs.






The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by Control Engineering subscribers. Vote now (if qualified)!
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
HMI effectiveness; Distributed I/O; Engineers' Choice Award finalists; System Integrator advice; Inside Machines
Women in engineering; Engineering Leaders Under 40; PID benefits and drawbacks; Ladder logic; Cloud computing
Robotic integration and cloud connections; SCADA and cybersecurity; Motor efficiency standards; Open- and closed-loop control; Augmented reality
Programmable logic controllers (PLCs) represent the logic (decision) part of the control loop of sense, decide, and actuate. As we know, PLCs aren’t the only option for making decisions in a control loop, but they are likely why you’re here.
This digital report explains how motion control advances and solutions can help with machine control, automated control on assembly lines, integration of robotics and automation, and machine safety.
This article collection contains several articles on how advancements in vision system designs, computing power, algorithms, optics, and communications are making machine vision more cost effective than ever before.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Control room technology innovation; Practical approaches to corrosion protection; Pipeline regulator revises quality programs
Cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by Control Engineering subscribers. Vote now (if qualified)!
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
HMI effectiveness; Distributed I/O; Engineers' Choice Award finalists; System Integrator advice; Inside Machines
Women in engineering; Engineering Leaders Under 40; PID benefits and drawbacks; Ladder logic; Cloud computing
Robotic integration and cloud connections; SCADA and cybersecurity; Motor efficiency standards; Open- and closed-loop control; Augmented reality
Programmable logic controllers (PLCs) represent the logic (decision) part of the control loop of sense, decide, and actuate. As we know, PLCs aren’t the only option for making decisions in a control loop, but they are likely why you’re here.
This digital report explains how motion control advances and solutions can help with machine control, automated control on assembly lines, integration of robotics and automation, and machine safety.
This article collection contains several articles on how advancements in vision system designs, computing power, algorithms, optics, and communications are making machine vision more cost effective than ever before.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Control room technology innovation; Practical approaches to corrosion protection; Pipeline regulator revises quality programs
Cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by Control Engineering subscribers. Vote now (if qualified)!
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
HMI effectiveness; Distributed I/O; Engineers' Choice Award finalists; System Integrator advice; Inside Machines
Women in engineering; Engineering Leaders Under 40; PID benefits and drawbacks; Ladder logic; Cloud computing
Robotic integration and cloud connections; SCADA and cybersecurity; Motor efficiency standards; Open- and closed-loop control; Augmented reality
Programmable logic controllers (PLCs) represent the logic (decision) part of the control loop of sense, decide, and actuate. As we know, PLCs aren’t the only option for making decisions in a control loop, but they are likely why you’re here.
This digital report explains how motion control advances and solutions can help with machine control, automated control on assembly lines, integration of robotics and automation, and machine safety.
This article collection contains several articles on how advancements in vision system designs, computing power, algorithms, optics, and communications are making machine vision more cost effective than ever before.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Control room technology innovation; Practical approaches to corrosion protection; Pipeline regulator revises quality programs
Cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me