Analysis of the structure and key technologies of intelligent substation

The intelligent substation adopts advanced, reliable, integrated and environmentally-friendly intelligent equipment. It takes the basic information of the whole station information digitization, the communication platform network and the information sharing standardization as the basic requirements, and automatically completes the basic functions of information collection, measurement, control, protection, measurement and detection. At the same time, it has substation that supports advanced functions such as real-time automatic control of power grid, intelligent adjustment, online analysis and decision-making and collaborative interaction.

The intelligent substation mainly consists of two parts: intelligent high-voltage equipment and substation unified information platform. Intelligent high-voltage equipment mainly includes intelligent transformers, intelligent high-voltage switchgear , and electronic transformers. The intelligent transformer and control system are connected by communication fiber, which can timely grasp the transformer status parameters and operation data. When the operation mode changes, the device decides whether to adjust the tap according to the voltage and power of the system; when there is a problem in the equipment, it will issue an early warning and provide status parameters, etc., to reduce the operation and management costs to a certain extent, reduce hidden dangers, and improve Transformer operation reliability. Intelligent high-voltage switchgear is a high-performance switchgear and control device with electronic devices, sensors and actuators with monitoring and diagnostic functions. The electronic transformer is a pure optical fiber transformer, a magneto-optical glass transformer, etc., which can effectively overcome the shortcomings of the traditional electromagnetic transformer. There are two functions of the unified information platform of the substation. One is the horizontal information sharing of the system, which is mainly manifested by the unification of information acquisition by various upper-layer applications in the management system. The second is the standardization of vertical information of the system, which is mainly manifested by the application of each layer to its upper layer. The transparency of the support.

Advantages of intelligent substation:

1. Intelligent substation can achieve good low carbon environmental protection effect

In smart substations, traditional cable wiring is no longer used in engineering. Instead, fiber-optic cables are used, and high-integration and low-power electronic components are widely used in various electronic devices. In addition, traditional oil-filled mutual inductance The device did not escape the fate of being eliminated, and the electronic transformer replaced it. Regardless of the improvement of various equipments and wiring means, energy consumption and waste are effectively reduced, which not only reduces the cost, but also effectively reduces the damage caused by electromagnetic, radiation and other pollution inside the substation to people and the environment. The quality of the environment has been greatly improved, and the performance of the substation has been optimized to make it more effective in environmental protection.

2. Smart substation has good interactivity

The operational characteristics and burden responsibilities of intelligent substations make it necessary to have good interactivity. It is responsible for the data statistics work of the grid operation, which requires him to have the function of returning safe, reliable and accurate information to the grid. After implementing the information collection and analysis functions, the intelligent substation can not only share this information internally, but also interact well with more complex and advanced systems within the network. The interactivity of the smart grid ensures safe and stable operation of the grid.

3. Reliability characteristics of intelligent substation

One of the basic requirements of customers for electrical energy is reliability. The intelligent substation has high reliability and meets the needs of customers while achieving high-quality operation of the power grid. Because the substation is a system, it is easy to take the phenomenon of pulling the whole body. Therefore, the substation itself and all the internal facilities have high reliability. Such characteristics require the substation to have the function of detecting and managing faults. This function can effectively prevent the occurrence of substation faults, and can quickly deal with them after the fault occurs, so that the working conditions in the substation are always in the best state.

The structure of the intelligent substation:

IEC61850 divides intelligent substation into process layer, bay level and station control layer, and high-speed network communication is used inside and between layers. The communication network of the whole system can be divided into: a station control layer communication network between the station control layer and the bay level, and a process layer communication network between the bay layer and the process layer.

The station control layer communication adopts the IEC61850 standard in full, and the monitoring background, telecontrol communication management device and protection information substation can directly access the IEC61850 device. At the same time, a complete IEC61850 engineering tool is provided to generate SCL files conforming to the IEC61850-6 specification, and data information can be exchanged between engineering tools of different manufacturers.

The bay level communication network adopts a star network architecture, and the horizontal interlocking function across the spaces is simultaneously realized on the network. The substation automation system with 110kV and below voltage level can adopt single Ethernet, and the substation automation system with voltage level above 110kV needs to adopt dual Ethernet.

Key technologies in intelligent substations:

1. References to distributed power sources in intelligent substations

Intelligent substation introduces distributed power supply, which can enhance the security and flexibility of the smart grid, and also significantly improve the operating efficiency. In addition, the existence of the single-thought-of-trend network is also changed in the power distribution system to radiate from the one-way power supply. The network has transformed into a multi-source network. The protection measures and protection behaviors in the original substation are all aimed at the single-trend network. Now the transformation of the single-trend network into a multi-network will make the previous protection behavior and protection measures no longer safe and reliable. According to this transformation, access to distributed power supplies poses a greater challenge to the role of smart substation relay protection.

2. Hardware integration technology in intelligent substation

With the continuous development and advancement of the smart grid, the hardware of the description language has begun to appear in the hardware system of the grid. The emergence of the hardware of the description language has made the intelligent substation integrated, automatic and modeled in design and application. The above characteristics make the functional system full of modular planning, which can solidify some different logic problems into the equipment inside the intelligent substation, and the software control reaches the hardware application. This ensures the accuracy and reliability of the design application and also solves the key problems in information transfer.

3. Component technology of software in intelligent substation

The software technology and hardware technology in the intelligent substation complement each other, and the two form a perfect collaboration. The software system is the soul and key to ensure the normal operation of the intelligent substation. It can not only realize information control and monitoring functions, but also integrate functions such as phasor measurement unit (PMU) and recording, which completes the regional disease inside the substation. Advanced functions such as control, online status monitoring, and remote operation. It is of far-reaching significance to ensure the safe and stable operation of an increasingly large and complex power system and to increase the degree of automation.