Simplifying protection system design for distribution substations

Orion New Zealand Limited (Orion) is a distribution utility that serves the city of Christchurch, the second largest city in New Zealand. Orion is adopting the technical capabilities found in the IEC 61850 standard and other technologies for a simple-to-implement, fit-for-purpose design for distribution protection. Orion is successfully using protective relays that provide multiple zones of protection in one device, and process bus communications, to simplify the design of their distribution protection. Careful system design allows the use of fewer protective devices, while maintaining the same level of protection system availability and reliability. Wiring and installation concerns are addressed by using process bus communications to provide remote I/O inputs for both analog measurements and digital control and status inputs, permitting the connection of only one cable to each relay. Benefits of this solution include a standard wiring design for all applications, fewer relay panels, faster installation, and simple expansion by simply connecting relays to process bus I/O units, while meeting performance requirements relating to device lifecycle, design and installation, safety, and commercial business requirements.