With Relay Testing It’s Knowledge First, Then Automation
I’ve always viewed relay testing as a craft, and protection engineers and technicians as craftspeople. Indeed, the manufacturers of relays and relay test sets also fit this moniker.
Computers, of course, are the principal accoutrements of the craft today, whether they be designed into the brains of protection system devices or equipment made to test them. Instructing such computers is the contribution of firmware and software code that opens possibilities for protection, automation, communication and control functions, and test cases, that may well be infinite.
There’s pride in this craft. It takes years for new relay technicians to reach proficiency given the multitude of test scenarios that various protection schemes demand of their knowledge and skills.
Tackling maintenance on electromechanical relays presents contact points to burnish and mechanisms to clean and adjust, aside from electrical values to calculate and inject during relay calibration tests.
Modern relays and protection IEDs replace mechanical principles of relaying with data and code in computerized devices, adding more functions to account for in test procedures.
Checking system components that are external to relays—secondary currents and voltages from CTs and PTs; the breaker trip coil circuit; DC from station batteries; communications equipment—takes careful reading of single-line diagrams and verifications that wiring is intact and properly terminated.
In digital protection schemes that are based on the IEC 61850 standard, technicians deal in communication protocols used between IEDs over ethernet which requires troubleshooting elements in substation networks that are virtual.
To succeed, relay technicians rely on the fundamentals of protective relaying to find concepts that guide their process with each new test situation they encounter. Over time, their experience and skills with testing different forms of protection applications are encapsulated in proven methodologies that characterize the craft.
Relay testing software provides technicians with a format to follow when testing and creates a test record that can be provided to administrators or other stakeholders. Many software functions can also automate steps within the overall test process.
I’ve heard arguments against automated testing. Valid arguments. Points I can’t dispute. “This isn’t for trained monkeys that just wanna push buttons and call it ‘good’…this is relay testing!”
I once got debriefed on how a training class went. The attendees were there to learn relay testing software but weren’t engaged. The instructor and one of the attendees got into a row about the point of the whole thing. As I heard it, the instructor finished things with, “the ones who learn this stuff are the ones who’ll get fired last!”
It doesn’t have to come to this. Passions aside, the craft of getting a relay into service “and calling it good” takes lots of cerebral horsepower from start to finish. But steps along the way that are repetitive with each and every test case don’t deserve the time of well-compensated professionals.
No amount of software will ever replace a relay technician’s knowledge—nor should it try. The purpose of automated testing is to give the qualified technician—whether new to the craft or at expert level—a rational, procedure-based approach to his or her job that can automate that which should be automated and leave the rest for human intervention with the human being in control either way.
Aside from automating device performance test sequences as defined, relay testing software can benefit a relay technician’s job with procedures that include manual-entry forms. Such tools guide human completion of requirements aligned to—or perhaps improving—existing processes.
The profile of relay testing is changing. The rise of inverter-based renewable energy; the increasing adoption of digital protection schemes based on the IEC 61850 standard; the possibility of virtual protection systems; the pervasive threat of cyberattacks; the demands of regulatory compliance mandates —these forces and perhaps a few others right now are tasking relay technicians like never before. The possibilities of modern protection systems are exceeded only by the consequences if something gets missed.
Quality relay testing software keeps things consistent. With consistency, deviations are easy to spot and troubleshoot. Relay technicians can design intelligence into automated tests that complement their knowledge and help them keep up without missing a step.
In the right hands and with the right mindset, automated testing, far from replacing a technician’s knowledge, demands great depths of it.
- Originally published in the The Relay™ Newsletter. Subscribe on LinkedIn.
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