Hue Power Company stated that in order to enhance the capacity of the equipment, reduce installed devices, simplify connections, and improve the reliability of the control protection system, an expert team at the company has designed a backup configuration solution to increase the reliability of the digital relay protection system.

Digital relay protection system at Phu Bai 110kV Substation

As of February 2025, Hue PC manages and operates 15 unmanned 110kV substations supplying electricity across Hue City. These substations are equipped with relay protection systems, SCADA automation, fire and smoke detection, and surveillance cameras. Among them, 14 substations follow the traditional model, while one has been built with digital technology.

To implement this solution, the technical team has collected all measurement and protection signals from current transformers (CT) and voltage transformers (VT) at feeder bays and configured backup functions on the protection control devices.

Especially, to increase the reliability of measurement signals from merging units (MU) for critical protection systems, the relay configuration follows the IEC 61850-9-2 standard, enabling configuration backup measurement signal function for protection systems based on the mechanism of selecting measurement signal sources from different MUs. The backup current circuit logic structure for feeder bay 171 is configured in the configuration software.

Backup current circuit logic structure.

Based on device status signals (health check and synch check), intelligent electronic devices (IED) can automatically select the input measurement signal source for the measurement signal processing blocks while also sending alerts regarding events related to measurement signal monitoring.

With this advanced solution, input data for critical measurement and protection systems will ensure continuity, enhancing system reliability and performance.

The technical team has also implemented a cross-backup method for relay protection systems using Process Plus. The Process Bus-based backup protection design enables the redundant backup model, duplicating protection functions on physically separate devices.

This solution was researched and implemented in May 2023 at the Phu Bai 110kV unmanned substation, which operates with fully digital technology.

With this solution, the research team has developed and mastered the technology for configuring backup settings, enhancing the reliability of the relay protection system using digital technology. The protection function backup design on the Process Bus allows optimal utilization of device capabilities, reducing installed devices, simplifying connections, and improving the reliability of the protection and control system.

At the same time, it enhances flexibility in developing methods for the protection and control system of the unmanned 110kV substation using digital technology, improves measurement and protection signals, and simplifies operation and management for the unmanned 110kV substation.

Translator: Thu Hường