As more IP-enabled electrical grids come online, they can provide advanced services such as telepresence conferencing, video monitoring, and office automation. Traditional Time-Division Multiplexing (TDM) grid communications networks, however, cannot effectively carry these services. Transforming communications over electric power grids needs:
Ultimately, electric power industry operators need to build a combined TDM/IP communications infrastructure that provides a variety of services and prevents multiple points of failure.
Huawei’s solution combines TDM with two IP-based networking methods:
Hybrid MSTP + IP and OTN/WDM + IP. An Automatically Switched Optical Network (ASON) ties the three methods together.
ASON is an “intelligent” optical network that interoperates well with legacy networks and automatically manages signaling and routing. Previously, it was necessary to configure cross-connections among network elements (such as an optical switch) to create a new traffic path. ASON also defends against multiple points of failure.
Hybrid MSTP + IP
A hybrid Multiple-Service Transmission Platform (MSTP) is based on mature optical transmission equipment, and builds a power transmission communications network that is compatible with existing grids.
IP-based communication is being introduced gradually by most of today’s electric power systems. However, differential relay protection, for example, needs to prevent delay and jitter, and can only use Synchronous Digital Hierarchy (SDH) for communication. That’s why so many power companies use an IP + SDH communication model for their grids. As a result, hybrid MSTPs are used to form a single ring, multiple-ring, or mesh network to carry IP, TDM, and other services. ASONs can be introduced into mesh networking to improve network reliability.
MSTP + IP highlights
- Reliable relay protection services facilitate the evolution of IP services
- Network failover time is 50 ms, protecting MPLS-TP packet services and ensuring hierarchical QoS
- Various grid services are carried uniformly and can be scaled up easily
OTN/WDM + IP networking
Huawei’s Optical Transport Network (OTN)/Wavelength-Division Multiplexing (WDM) method uses OTN/WDM devices to implement long-distance, large-capacity transmission. These meet the requirements for higher bandwidth to accommodate the growth of power grid communications services.
- As more substations are built, more services are needed
- Services include video conferencing, substation video monitoring, and online monitoring of power transmission lines
- Backbone network bandwidth requirements are expected to soon exceed 10 Gbit/s
- Ultra-High Voltage (UHV) and Direct Current (DC) long-distance transmission service will extend the distance between substations
- Huawei provides the industry’s longest single span — 380 km
The OTN/WDM method also protects operators’ network investments:
- A single fiber-optic line can support 8 Tbit/s bandwidth
- Maximum electrical cross-connection capacity of optical equipment can reach 6.4 Tbit/s
- ASON can resist multiple lightning strikes, thus ensuring reliable operations
- Failover time is less than 50 ms