Accelerating innovation in teleprotection services
The need to switch utility networks from legacy Time Division Multiplexing (TDM) technologies to fully IP-based technologies continues to increase as Distributed Energy Resources (DER) become critical components of restoring power to the transmission network during incidents like a black start. For the existing utility communication infrastructure to meet the growing deployment requirements of power networks of the future, packet-based technologies that are reliable, secure, and bandwidth-efficient like Multi-Protocol Label Switching (MPLS) have to be successfully and widely introduced in the power network to carry traffic of different critical applications. If the power networks are successfully migrated from the legacy critical teleprotection services to MPLS technology, this will lead to significant cost savings with improved overall system performance.
When it comes to power networks and critical applications such as teleprotections, deploying such technology will need to comply with the existing regulations, policies and standards of the power utility networks and the regulator. Engineering recommendations and guidance from standard organisations like the Energy Networks Association (ENA) and International Electrotechnical Commission (IEC) help develop and manage energy networks safely and reliably. In the UK, the National Cyber Security Centre (NCSC) policy and guidance ensure the security of energy supply. Any use of new IP/MPLS and MPLS/TP for teleprotection must ensure that the communications services and teleprotection systems remain stable during any protective switching events.
The aim of the MPLS project at PNDC:
Verify teleprotection service stability and speed over MPLS hitless technology.
Demonstrate the capabilities of MPLS technologies (IP MPLS and MPLS TP technologies are tested) and validate their implementation over High Voltage (HV) Teleprotection line.
Evaluate the performance of various telecommunication vendors’ platforms to deliver the most critical current differential protection services and provide flexible and reliable network path switching capabilities.
Real-Time Digital Simulator (RTDS) testing to verify the performance requirements and the functionality of the MPLS communications service by applying different types of faults to the simulated high voltage power line.
Three-ended line differential protection scheme with the actual setting values based on real line parameters were used.
10G Data network analyser that injects the Bit Error Rate (BER), jitter and latency and creates various data network conditions.
The MPLS setup at PNDC consists of several MPLS Nodes with dual CPUs which support hitless technology over different communication and teleprotection interfaces such as C37.94, Analogue VF, serial data card and X.21 digital card were used.
Measurement and monitoring of communication latency, relay tripping times, communication network stability and relay stability and speed under different data network conditions.
Three-ended line differential protection scheme
The overall test results of MPLS Hitless technologies are summarised below:
MPLS hitless networks, when appropriately configured, can meet the strictest latency and asymmetry requirements for substation teleprotection communication. Quality of Service (QoS) prioritisation, as evaluated, ensures that teleprotection packets are transmitted without being queued or delayed under different network congestions. The fail-over times with the present hitless MPLS feature were neglected.
PNDC lab testing has also clarified that Hitless MPLS networks are sufficient communications media for teleprotection applications if designed and configured correctly to meet the critical teleprotection requirements in terms of end-to-end delay and asymmetrical latency.
PNDC offers the possibility to carry out extensive testing of packet based transport technologies such as MPLS-TP and assess their reliability in a real world environment. Happy to collaborate again in future networks projects.
Nokia has been working with PNDC to provide assurance in both fixed IP MPLS and 3gpp technology solutions for DNO / Utility operations. Independent verification at PNDC in a safe harbour test is vital to test and secure the predictability needed for the UK’s critical distributed energy resources. Especially so in building an active and secure network evolution.
Our areas of collaborative test with PNDC and DNO’s have included the telecom verification in control protection (Teleprotection) and field area automation.