It is the second physical network of the power system. It is an important part of the power grid. It is the foundation of power grid dispatch, operation, and management information. It is an important means to ensure the safe, stable and economic operation of the power grid; I think it can be used as a metaphor. Our power grid is the human body’s arteries (UHV) and capillaries (urban distribution network), which deliver blood (that is, electric energy) to various tissues of the human body. The communication network plays a role in transmitting, controlling, and regulating signals to the human body, just like our neural network. Electric power communication has been developing along with the power grid, from the initial analog circuit switching to the current SDH, WDM, and OTN. The transmission rate is getting higher and higher, and the capacity is getting bigger and bigger.
The communication network is divided into a backbone communication network and a terminal access network. According to the function, it is divided into transmission network, business network and support network. We can also make an analogy like this: the transmission network is a highway, an information highway, and the bandwidth can also be understood as a very wide road with 8 lanes in both directions. Business network-refers to the specific types of vehicles that run on the road, which can be trucks, tank trucks, cars, and even electrified work vehicles. Support network-is to play a role of control and supervision, just like our traffic police, road administration, there are a series of traffic rules, there are signal lights, coordinated, and the flow of traffic must be cleared when blocked.
Transmission network, it is the basic network of power communication, composed of transmission medium and transmission equipment. The transmission medium of the electric power communication network mainly includes optical cables, radios and power transmission lines, corresponding to optical fiber communication, microwave, satellite communication, power line carrier communication and other methods respectively.
At present, optical fiber composite overhead ground wire (OPGW) and all-dielectric self-supporting optical cable (ADSS) are mainly used in power communication. According to the erection method, it can be divided into several methods such as pipeline, overhead, and direct buried. OPGW is an O cable, a new structure ground wire used in high-voltage power transmission systems, which has the dual functions of an ordinary overhead ground wire and a communication optical cable. ADSS is a non-metallic optical cable that is composed of dielectric materials and contains necessary supporting systems. It can be directly suspended on power poles, but it is susceptible to electrical corrosion.
OTN technology is based on WDM (Wavelength Division Multiplexing) technology, integrating the advantages of SDH technology, large crossover, and ultra-bandwidth. Currently, it has been applied in the network province company scale, and the bandwidth has reached more than 40G.
Industrial Ethernet switches have the characteristics of high real-time, high security, high and low temperature resistance, anti-vibration, anti-electromagnetic interference, etc., and are widely used in substation automation systems, power distribution automation and other services.
Power line carrier communication is a wired communication method in which power lines are used as information transmission media for data transmission. It is a unique communication technology for power systems. It covers a large area and is easy to install, but it also has shortcomings such as strong attenuation, strong noise, time-varying characteristics, unknown topology, and high electromagnetic compatibility requirements.
Microwave communication is what we are talking about. It is mainly used as a backup channel in power communication. The communication capacity is large, the construction speed is fast, and it is easy to cross complex terrain. The topology is not affected by a line change. It is susceptible to atmospheric and terrain factors, especially in the case of high-bandwidth transmission.
The satellite communication system is actually a kind of microwave communication. It uses satellites as relay stations to forward microwave signals, which are the lids flying in the sky. It continues to play a role in the field of emergency communications and in the process of handling emergencies. Satellite communications are used for emergency repairs in Wenchuan and Lushan earthquake-stricken areas.
The wireless private network is based on the dedicated frequency band allocated to the power system by the State Radio Management Committee. Mainly used for collection of electricity consumption information and power distribution automation.
Electric power communication network-business network
The service network is an application network built on the basis of the transmission network and meeting the needs of different power grid management services under the coordination of the support network. The current business network mainly includes administrative telephone exchange network, dispatch telephone exchange network, data communication network, conference video telephone system, etc.
The data communication network is mainly composed of routing and switching equipment, which can realize data and image multiple services and services. Different services are carried by different MPLS VPN (virtual private network) technologies. At present, the data communication network carries management information services such as administrative office and marketing.
Administrative Telephone Switching Network: Currently, circuit switching is mainly used, and some companies have deployed softswitches, which will evolve to IP multimedia subsystems in the future.
Dispatching Telephone Switching Network: The special telephone switching network for power grid production and dispatching is the basis of power grid dispatching automation and management modernization. From the headquarters to the substation, there is the last part of these five levels, the support network: it is used to ensure the normal operation of the business network, enhance network functions, and improve network service quality. Corresponding monitoring and control signals are transmitted in the support network. The company's support network mainly includes synchronization network and network management network.