IEC 61850 Ready and NCITs

Non Conventional Instrument Transformers (NCIT) and IEC 61850 compatible products From RHM International

IEC 61850 is an important new international standard for substation automation that will have a very significant impact on how electric power systems are designed and built for many years to come.

IEC 61850 provides a comprehensive model for how power system devices should organize data in a manner that is consistent across all types and brands of devices. This eliminates much of the tedious non-power system configuration effort because the devices can configure themselves.

For instance, if you put a CT/VT input into an IEC 61850 relay, the relay can detect this module and automatically assign it to a measurement unit without user interaction.

How do Non-Conventional Instrument Transformers (NCITs) work in the 61850 substation?

At the “process” layer, data from Optical/Electronic Voltage and Current sensors as well as status information will be collected and digitized by the Merging Units (MUs). MUs could be physically located either in the field or in the control house. Data from the MUs will be collected through fiber optic Ethernet connections. The collection points will be Ethernet switches with internal data buses. In migrating to Process Bus implementations, manufacturers will need to provide the ability to integrate data from existing CTs and PTs with the data from the newer Optical/Electronic sensors (NCITs).

A redundant synchronization clock architecture will also have to be addressed. In this architecture, upon detection of failure of Clock 1, Clock 2 will have to automatically come on line and continue providing sampling synchronization. The following diagram summarizes the architecture:

RHM International’s dry type core insulation technology makes it particularly easy to provide IEC 61850 compatible equipment. Our patented design allows an easy sensing and digitalizing of the signals at the ground level, similar to traditional analog equipment that it may replace.

Monitoring through 61850 compatible sensors.

RHM International’s built-in monitoring systems have been developed to provide an easy interface with the transmission protocols of the IEC 61850 standard. Integration of the monitoring into the overall substation digitalization provides two advantages; a reliable and straightforward analog sensing and a ready to connect digitalized signal.

IEC 61850 Ready RHM International Products