Experiences with IEC 61850 in commissioning a high voltage reactor, by Jason Buneo, Dhanabal Mani and Rene Aguilar, Megger US.
IEC 61850 enabled substations are becoming increasingly common. Despite the many benefits that result from implementing the IEC 61850 standard, significant challenges remain.
The first edition of the IEC 61850 standard was released in 2005 and adopted by utilities across the world as a viable solution for substation protection. The standard first came about as separate initiatives. These included UCA 2.0 from the Electric Power Research Institute (EPRI), as well as IEC 60870-5101, IEC 60870-5-103, and IEC 60870-5-104 from the International Electrotechnical Commission. In 1997, the initiatives were combined as part of an internationally agreed process to become a full standard.
One of the aims of that process was to allow communication in substations between intelligent electronic devices (IEDs) originating from different manufacturers. Prior to the release of the standard, proprietary network protocols hampered communications between competing IEDs, with the result that such communication was reduced to either direct wiring via input/output contacts or the use of low-speed serial connections.
In contrast, implementation of the IEC 61850 standard now allows substation devices to be part of a local area network (LAN) based substation, with high-speed peer-to-peer communications. The advantage of the LAN based approach is that simple or complex control schemes can be easily implemented without increasing the complexity of the physical wiring. In a LAN based protection scheme using the IEC 61850 standard, the primary form of communication between protective devices is the Generic Object Oriented Substation Event, or GOOSE message.
Commissioning a substation with automation that includes IEDs communicating via GOOSE messaging proved to be a challenging task.
After commissioning of the substation, an additional circuit breaker needed to be added as a logical node in one of the ICD files protecting the shunt reactor. The new ICD file was uploaded to the IED. Shortly after, there was an incident with the shunt reactor.
During the hottest part of the day and at peak load, a fault occurred that triggered the sudden pressure alarm. The pressure relief valve operated, spraying oil over a wide area, and a pressure relief valve trip signal from the reactor IED was sent to the bay control IED. However, the bay control failed to send a GOOSE message to the breakers responsible for isolating the line, and it was necessary to manually open the breakers to clear the fault.
An investigation was conducted to determine why the breakers did not operate properly to clear the fault. It was found that the change made to the bay control IED protecting the reactor meant that this did not have the same substation configuration language (SCL) file as other IEDs on the system. Because of this discrepancy, all of the trip signals from this IED were ignored. Since the SCL file from the reactor IED did not match the file in the other IEDs, as far as the rest of the network was concerned, GOOSE messages sent from the reactor IED should be ignored.
Corrective action was taken and all of the IEDs were updated to the same SCL configuration. The logic was retested and the substation was brought back online.
As acceptance of the IEC 61850 standard becomes more and more widespread, it is important to be mindful of previous oversights so that potential catastrophic failures can be avoided. Megger has introduced the SMRT46 and the SMRT410 which provides IEC 61850 testing capabilities. The SMRT46 is a multipurpose, light-weight, field portable test set capable of testing a wide variety of electro-mechanical, solid-state and microprocessor-based protective relays, motor overload relays and similar protective devices. The SMRT46 has the “smart” combination of small size, light weight, with high power.
The SMRT410 provides a complete multi-phase test system for commissioning of protection systems. The SMRT410 VIGEN modules also provide high power in both the voltage and current channels to test virtually all types of protective relays.
The authors are (Jason Buneo) Applications development manager, (Dhanabal Mani) Applications development engineer and (Rene Aguilar) Senior application engineer, Megger US. For SMRT series details visit en.megger.com