Implementing Pilot Protection Schemes Over National Grid Owned Mpls-Tp Network
Prompt fault clearance and the minimization of power outages are top priorities for electric utility companies. The National Grid system currently employs pilot protection schemes over leased DS-0 and DS-1 (T1) circuits, as well as dedicated dark fiber. However, the DS-0 circuit is being phased out, and the T1 circuit is expected to follow suit in the near future. Additionally, the monthly recurring costs of leased circuits have risen significantly in recent years. It is now time to explore alternatives from available sources.
The existing company communication network, which is based on SONET technology and Data Multiplexer (DMX) equipment and protocols, is being upgraded to a new Multi-Protocol Label Switching - Transport Profile (MPLS-TP) or Carrier Ethernet IP-based communication network. This upgrade will support all current and future grid modernization technologies and functionalities. The MPLS communication network provides numerous advantages, including low latency and jitter, traffic engineering, fast rerouting, and compatibility with both legacy and modern protocols. Additionally, the communication interfacing equipment can be selected to support C37.94 fiber optics, 4-wire audio, Ethernet, and other serial communication ports, allowing connections to protection relays or Teleprotection devices.
The pilot protection schemes (POTT, DTT, DCB, line differential) have been tested over the company-owned MPLS network. Direct relay-to-relay communication, without dedicated tele-protection devices, using mirrored-bit and IEC-61850 GOOSE messages, was also evaluated. The test results from the fully deployed MPLS network are provided. The communication latency, asymmetry, and jitter were found to be satisfactory and met the requirements for high-speed protection.
After reading this paper, the reader will gain an understanding of the MPLS network, which offers a viable option for pilot protection with satisfactory performance at a lower cost.