Application of vertical integration and miniaturized protection equipment in the smart substation demonstration project of China Southern Power Grid

introduction

China Southern Power Grid Co., Ltd. proposed to build a "safe, reliable, green and efficient" smart grid. As the basic operating unit of the power grid, the intelligence level of the substation is a key link affecting the effectiveness of smart grid construction. In order to implement the design concept of "intelligent, modular and integrated" smart grid of China Southern Power Grid, based on the principles of clear trend, advanced technology, reasonable solution and convenient operation and maintenance, the construction of smart substation pilot project was carried out. Through the pilot project, we will promote technology iteration, promote innovative development, summarize and accumulate experience and technology promotion and application conditions, form an effective model, and guide the future development of smart substation of China Southern Power Grid.

Electrical secondary equipment has gone through a long period of development from early mechanical electromagnetic, transistor, and integrated circuit types to microcomputer automation devices, and then to the application of digital sampling and support for IEC61850 protocols. In today's smart substations, electrical secondary equipment is still mainly configured in the form of bay-oriented equipment, and protection and automation functions are hierarchically distributed in multiple devices at the bay layer, process layer, and station control layer to achieve information digitization and data sharing. However, there are also many problems in smart substations: due to the complexity of optical fiber connections and the large workload of virtual terminal configuration, virtual circuits are difficult to maintain, and sampling value synchronization is complex: the reliability of the vertical distribution of electrical secondary equipment functions decreases rapidly: the functions of process layer equipment are horizontally coupled, and the services affect each other: the optical port is heated, and the data synchronization is complex: each bay is equipped with protection devices, measurement and control devices, merging units or intelligent terminals, recording, metering and other devices, and the functions of each device are independent of each other, resulting in repeated hardware configuration, complex wiring of the entire station, insufficient information sharing, lack of coordination and function optimization of the entire station system layer, and high investment costs.

This paper mainly introduces the pilot application scheme of new intelligent substation technologies such as vertical integration and miniaturized secondary equipment in the electrical secondary specialty of Zhaoqing 110kV port power transmission and transformation project.

1 Network Structure

Zhaoqing 110kV Port Substation adopts conventional transformer + merging unit to realize digital sampling: SV and G00SE form a network together to realize information sharing and network sampling and network jumping. The network structure is shown in Figure 1.

Zhaoqing 110kV Port Substation adopts a "three-layer two-network" network structure. The three layers are station control layer, bay layer, and process layer, and the two networks are station control layer network and process layer network. The station control layer network adopts a dual-star redundant network structure, and is configured with MMSA and MMSB networks: the process layer network G00SE network is merged with the SV network, and a dual-star redundant configuration is adopted, so that the N-1 failure of the communication link does not affect any set of protection functions. The bay protection adopts direct sampling and direct tripping, and the cross-bay protection such as main transformer protection and bus differential protection collects current, voltage, measurement and control information through the process layer G00SE + SV network, and sends a tripping message through the G00SE network to achieve network sampling and network tripping.

The main function of the station control layer equipment is to collect real-time data information of the entire station through the network, continuously refresh the real-time database, and regularly transfer the data to the historical data record library; send relevant real-time data information to the dispatching end as needed; receive control and adjustment commands from the power grid dispatching or control center and send them to the interval layer and process layer for execution; have the function of station-wide operation locking control and local monitoring and human-computer contact within the station; have the function of online maintenance and parameter modification of secondary equipment at the interval layer and process layer.

The main equipment configured in the interval layer includes various protection devices, measurement and control devices, intelligent recorders, station area protection, etc. Its main function is to summarize the real-time data information of each interval process layer: complete the calculation, judgment, and command of various protection, automatic control, and logical control functions; complete the judgment of the interlocking/locking and synchronous functions of each interval and the entire station operation; execute the data communication transmission function, and at the same time complete the network communication function with the process layer and the station control layer.

The main equipment at the process layer is the merging unit, intelligent terminal and integrated security, measurement and intelligence equipment. Its main function is to monitor the equipment operating status, execute control commands, etc.

2. Vertical Integration

The vertical integration solution is based on the interval hardware integration device. It integrates the merging unit, intelligent terminal, protection, measurement and control equipment into the interval, arranges them on-site, simplifies the logic within the interval, realizes cross-interval information network sharing, and realizes standardized interface with primary equipment in the form of interval on-site control cabinet, prefabricated optical cable connection, cross-interval information network hopping, information sharing, network optimization, and solves the problems faced by electrical secondary equipment.

Zhaoqing 110KV port substation adopts interval-based hardware integration device. The 110KV line integrates merging units, intelligent terminals, protection, measurement and control equipment for the interval, arranges them on-site, simplifies the logic within the interval, and shares information network across intervals.

3Miniaturized secondary equipment

Centralized layout, forming secondary equipment cabinets through miniaturized equipment, optimizing and integrating screen positions, and realizing standardized interfaces. Network procurement and network jump, information sharing, and network optimization.

3.1110kV miniaturized busbar protection solution

The Zhaoqing 110KV Port Substation is equipped with a set of 110KV miniaturized busbar protection devices, including 110KV segmented overcurrent protection function, SV network sampling, GooSE network tripping, and a 4U height 19/2-inch plug-in chassis. The 110KV miniaturized busbar protection scheme is shown in Figure 2.

At present, the 110KV busbar protection screen of the Southern Power Grid V2.1 smart substation is equipped with one 110KV busbar protection (including segment protection function) and one printer; the 110KV busbar PT and segment measurement and control screen is equipped with two 110KV busbar PT measurement and control devices and one 110KV segment measurement and control device.

The 110KV busbar protection panel of the Zhaoqing 110KV Port Substation is equipped with one 110KV miniaturized busbar PT measurement and control device, one 110KV miniaturized segmented measurement and control device, one 110KV miniaturized busbar protection (including segmented protection function), and network printing. Compared with the CSG V2.1 version of the smart substation, it saves one panel cabinet, one 110KV busbar PT measurement and control device, and one printer.

3.2110kV miniaturized main transformer protection solution

The main transformer of Zhaoqing 110KV Port Substation is equipped with dual main and rear integrated miniaturized transformer electrical quantity protection and a set of main body non-electric quantity protection. The main body non-electric quantity protection is integrated into the main body intelligent terminal. The non-electric quantity protection adopts on-site direct cable tripping, and the information is sent to the process layer GooSE network through the main body intelligent terminal. The printer is cancelled in the main transformer protection screen and replaced by network printing. The equipment adopts a 4U height 19/2-inch plug-in chassis. The 110KV miniaturized main transformer protection scheme is shown in Figure 3.

Taking a single-branch main transformer as an example, at present, the 110KV main transformer protection screen A of the Southern Power Grid V2.1 version of the smart substation is equipped with 1 main transformer protection and 1 printer; the main transformer protection screen B is equipped with 1 main transformer protection and 1 printer; the main transformer measurement and control screen is equipped with 1 high-voltage side and main body measurement and control device and 1 low-voltage side measurement and control device.

Zhaoqing 110KV Port Substation 110KV main transformer protection screen A, 1 miniaturized main transformer protection, 1 miniaturized main transformer high voltage side and body measurement and control, 1 miniaturized main transformer low voltage side measurement and control, using network printing: Main transformer protection screen B, 1 miniaturized main transformer protection, using network printing: Compared with the Southern Power Grid v2.1 version of the smart substation, it saves 1 screen cabinet and 2 printers.