Advantages of smart substations over traditional substations

Abstract: With the continuous development of the national economy, people's living standards and quality of life are constantly improving, and there are more and more household appliances and personal computers. Traditional substations can no longer guarantee the quality of power to meet the daily electricity needs of the public. It has become an irreversible trend for smart substations to replace traditional substations.
 

A substation is a place where voltage is changed. In order to transmit the electricity generated by a power plant to a distant place, the voltage must be increased to high voltage, and then the voltage must be lowered as needed near the user. This work of raising and lowering voltage is done by the substation. According to the different internal implementation principles, substations can be divided into traditional substations and smart substations (also known as digital substations). After the traditional substation entered the 1990s, its inherent defects and limitations were increasingly exposed.

 

Figure 1 Structure diagram of traditional substation and digital substation
 

From traditional substations to smart substations, the differences are mainly divided into three aspects:
 

1. Intelligent primary equipment
 

The intelligence and informatization of primary equipment is the key to realizing the informatization of smart grid. Using standard digital and informatization interfaces to realize intelligent primary equipment integrating online detection and measurement, control and protection technology can realize the demand for the integration of information flow of the entire smart grid. The equipment layer of the smart substation inherits all the functions of the process layer and the interval layer of the traditional substation.
 

2. Equipment maintenance status
 

Online detection of equipment status is a new function, which is one of the core differences between smart substations and traditional substations. Intelligent primary equipment uses advanced status detection methods, reliable evaluation methods and life prediction methods to determine the operating status of primary equipment, and conducts fault analysis on equipment when the operating status of primary equipment is abnormal, and makes judgments on the location, severity and development trend of the fault. It can identify early signs of faults and perform maintenance based on the analysis and diagnosis results before the equipment performance drops to a certain level or before a fault occurs.
 

In traditional substations, only a few transformers are equipped with online monitoring devices. In the field of smart substations, not only transformers, but also GIS, SF6 circuit breakers, disconnect switches and other major primary equipment need to be equipped with online detection equipment.
 

3. Secondary equipment networking
 

Secondary equipment of substations, such as relay protection, detection and control devices, motion devices, fault recording settings, reactive power compensation, network security detection equipment, etc. All the connections between these devices use high-speed network communication, and there will be no repeated I/O field interfaces of conventional functional devices, and data sharing and resource sharing can be truly realized through the network. It can be said that the networking of secondary equipment is to realize distributed system control through IEC61850 protocol, optical fiber and other equipment, thereby replacing the bus mode, making data transmission richer and more standardized, which also provides a guarantee for the "panoramic" monitoring of smart substations.
 

The DT6000 series intelligent substation optical digital analyzer is based on the IEC61850 standard and is widely used as a handheld test instrument for intelligent substations with voltage levels of 110kV and above. It is used for quick testing of protection and control devices, intelligent terminals, merging units, transformers and other equipment in digital substations, facilitating the establishment and maintenance of digital substations. It is the Swiss Army Knife of digital substation testing.