A brief discussion on the layout of communication cabinets in UHV substations

Keywords Design and layout
of communication cabinets in UHV substations Abstract The layout of communication cabinets in UHV substations should be based on the final design of the substation, in accordance with the principle of simplification of signal flow, and overall consideration of uniformity and particularity. The equipment should be arranged according to the signal flow, so that the links are simplified and the routing of the main signal cables is minimized, while avoiding poor quality as much as possible and minimizing crossover.
1 About the hierarchical partitioning of signal equipment
For the entire UHV substation communication system, the fourth most critical part of safety automation is to ensure the effective transmission of line relay protection signals. According to the importance, 1000kV and 500kV are the focus of line protection signal transmission. If the design of 12 circuits of 500kV lines and 8 circuits of 1000 kV lines in the UHV substation is used, in the 16-way 1000kV line signal transmission business, 4 sets of 1000kV optical transmission equipment and 16 sets of 1000kV line remote interface equipment are generally configured in the telecontrol communication room. According to similar reasoning, the corresponding telecontrol communication room should also be equipped with 4 sets of 500kV optical transmission equipment and 24 sets of 500kV line remote interface equipment. Drawing on the experience of the optical transmission network, only the same-layer optical cross-connection and downward optical access functions are performed at the backbone layer; only the upward optical access and downward electrical access functions are performed at the convergence layer; and only the upward electrical access and other functions are performed at the access layer. In this way, the main signals carried by the UHV substation are configured in layers and partitions.
2 Communication cabinet layout
After completing the layered and partitioned configuration of communication signal equipment, the most critical and important line protection signal transmission business in the UHV substation should be fully considered. The dedicated optical terminal for line protection and the line protection interface equipment can be set together in the 1000 kV or 500 kV protection room.
First, after configuring the dedicated line protection convergence layer 155/622M optical transceiver, two 8-system digital distributions, two DC/DC (-220V/-48V) power converters and one optical distribution should be configured in the optical transmission equipment panel; second, the A-1-1 optical transceiver and the B-1-1 optical transceiver are mutually cold standby, and the A-2-1 optical transceiver and the B-2-1 optical transceiver are also mutually cold standby. If only one AUG time slot is allocated, then the 8 time slots allocated by TUG3 (1) can be connected to 8 2M branches to the lower port of the digital distribution, and the 2M lines of the 4 sets of interface devices connected to the upper port on the back of the digital distribution also become odd ports. The 8 time slots allocated by TUG3 (2) can be connected to 8 2M branches to the lower port of another digital distribution as cold standby. Use 2M jumper on B-1-1 optical transmission equipment panel and A-1-1 optical transmission equipment panel. Once A-1-1 optical terminal fails, open the digital distribution tee of A-1-1 optical transmission equipment panel, connect 2M jumper to the upper port, open the digital distribution panel tee of cold standby equipment, connect 2M to the lower port of digital distribution, and it can be realized as long as two substations are operated at the same time.
3 Power supply and communication monitoring equipment configuration
Because the line protection dedicated optical terminal and line protection interface equipment have completed the pre-placement work and are pre-placed in the 1000kV or 500kV protection room, a DC/DC power converter should be configured in each line protection dedicated optical terminal panel, and the protection interface equipment of the optical terminal should be provided. Three sets of high-frequency switching power supply systems can be configured in the telecontrol communication room. Information Network The power supply of switches and many network management equipment can be extracted from the telecontrol professional inverter power supply feeder panel. An AC distribution panel is configured in the communication panel queue to provide power to information network switches and network management equipment. The communication power information can be collected in a soft way, and the protocol conversion can be completed by software. 4 Several issues to be considered in the design 4.1 Terminal block design In the typical panel cabinet design, the terminal block numbering should be carried out according to the principle of unit segmentation and concentration, and the AC current (voltage) circuit, operating positive power supply, signal output circuit and high-frequency channel should be sorted according to the principle of top-down. The connection between the devices in the panel cabinet should be realized through the transfer of the terminal block to avoid mutual interference between the devices and make the terminal block design more compact and simple. 4.2 About the duplication of the tripping circuit In order to thoroughly implement the requirements of the State Grid Corporation of China on preventing major production accidents, the panel cabinet design can adopt a phase-splitting operation box with a double tripping coil, and at the same time set a set of DC power switches in each set of its tripping circuit. For the line protection with dual configuration, each set of protection can only lead one pair of tripping contacts to the tripping coil, instead of each set of protection leading to two pairs of tripping contacts. This method can not only protect the duplication of the tripping circuit, but also avoid cross-overlapping and make the circuit too complicated.

4.3 Switching of fiber optic protection bypass
When the bypass circuit breaker is used to replace the line, the bypass fiber optic permissive distance protection can be formed by switching the fiber optic interface device to the bypass. This method has a wide range of adaptability to various situations.
4.4 Remote reset transceiver
In the past application of LFP series protection, the reset transceiver could only be achieved by the operator through the reset button on the screen. Because it is necessary to test whether the high-frequency channel is intact every day, the workload of the on-site operator to manually reset the transceiver is relatively large. Therefore, the protection needs to increase the remote reset transceiver contact. In the optimized design, the contact and the manual reset transceiver button on the cabinet can be connected in parallel, and the reset transceiver can be achieved by the operator through the workbench through the protection device.
4.5 Non-full-phase protection during bypass
In the past, when the bypass replaced the main transformer, it was usually not possible to switch to bypass. In the optimization design, the non-full-phase protection of the failure starting device of the bypass protection cabinet can be considered when designing the bypass, so as to achieve non-full-phase protection conditions during the operation of the bypass replacing the main transformer.
4.6 Coordination with the integrated automation station
The panel cabinet should be considered in the way of the integrated automation station. The remote and local switching switches cannot be installed on the line protection cabinet, but should be installed on the line measurement and control cabinet. In addition, because the measurement and control cabinet adopted by the integrated automation station can only provide manual jump and manual closing contacts, a double-position intermediate relay should be added to the operation box.
4.7 It should be easy to maintain and diagnose
The operation control tool monitors the operating status of each node and link of the front-end system, and should be able to actually control various operating modes such as stopping, deleting, and restoring. The message monitoring tool can also monitor the sending and receiving information of multiple running channels in real time at the same time, and should be able to intercept and store in the file for specific analysis of the message. The system operation management subsystem is responsible for maintaining the startup operation and status monitoring of these processes. Once an abnormality occurs in these processes, the system should immediately start the fault recovery mechanism to ensure the normal operation of the system.
In addition, there are dispatching automation issues in three specialties such as telecontrol, communication and information in the UHV substation. At present, many dispatching agencies and hub substation monitoring rooms have realized the non-computer hostization of dispatching seats , that is, the traditional dispatching computers are moved to the server screen, and only peripherals such as monitors and keyboards are placed on the dispatching seat desktop, and the peripherals are connected to the host through an extender. If there are a large number of computers, a soft switching KVM can be installed in the server screen. De-hosting the dispatching seat can fundamentally solve the long-standing host heat dissipation problem, and the corresponding problems such as the large number of dispatching seat cables and power supply guarantee are also solved. 5 Conclusion There are other details that are easy to overlook in the UHV substation, including the design of information systems and integrated wiring systems. For these problems, according to the relevant requirements of the State Grid Corporation on the construction of the command system, the corresponding emergency command room should be established, the production dispatching conference television system should also be organically combined, and the equipment, environment, power supply, etc. should be considered comprehensively, and experience should be constantly summarized , and continuous improvement should be made, and efforts should be made to accurately design the layout to every end link, to ensure convenience and simplicity to the maximum extent, and to ensure the reliability of operation and maintenance. References [1] Fan Chen, Chen Xiaochuan, Ma Yanyu, et al. Research on substation configuration based on IEC61850[J]. Relay, 2007(8): 41-44. [2] Zheng Yiwen, Chen Yiwei. Digital substation communication network solution[J]. New Viewpoint, 2008(27): 11-13.