With the rapid construction of smart substations, there are a large number of highly intelligent devices inside such substations, making the equipment operation processes more complex and significantly increasing the workload of operation and maintenance personnel. The existing control methods of smart substations can no longer meet the current development and operation and maintenance requirements of the power grid. In accordance with the latest specifications and standards of the State Grid, misoperations shall be minimized: the disconnecting switches of smart substations must be equipped with remote control functions, yet on-site manual inspection of equipment status is required after operation.

The "One-Click Sequential Control" technology for smart substations can replace manual on-site verification. The system automatically verifies the equipment operation status before operation, streamlines the operation process, improves the accuracy, effectiveness and efficiency of electrical operations in substations, reduces the work intensity of operation and maintenance personnel, and enhances the safety level of switching operations of power grid equipment.

At present, the monitoring systems of some smart substations cannot expand the sequential control function through software upgrades, which is difficult to meet the sequential control requirements. Therefore, it is necessary to carry out the transformation of the sequential control system for substations, and add new devices including substation disconnecting switches, micro switches (double confirmation of knife switch position), background monitoring host, independent sequential control host and independent intelligent anti-misoperation host. Specifically, knife switch travel micro switches and integrated measurement and control devices are newly installed in the substation, which access the signals such as the on-site knife switch status and transmit them to the "One-Click Sequential Control" host as the double confirmation condition for the "One-Click Sequential Control" operation ticket. A set of "One-Click Sequential Control" operating system is added in the substation to enable the primary equipment of the substation to have the "One-Click Sequential Control" operation function. This "One-Click Sequential Control" system operates in parallel with the original system without mutual interference.

△ Architecture of the "One-Click Sequential Control" System

Architecture of the "One-Click Sequential Control" System

The sequential control host is responsible for the storage and management of "One-Click Sequential Control" operation tickets, real-time reception and execution of locally issued "One-Click Sequential Control" instructions, and completion of tasks such as task generation, simulation preview, instruction execution, anti-misoperation verification and operation recording, and uploads the execution results. The simulation preview and instruction execution adopt the verification principle of the built-in anti-misoperation mechanism, with anti-misoperation verification carried out in parallel. The operation can only be continued after the verification is passed to prevent misoperations. If the verification fails, the operation will be terminated and detailed error information will be prompted.

Installation of the "One-Click Sequential Control" System

Before on-site implementation, conduct on-site surveys to confirm the installation positions of the sequential control screen cabinet and knife switch micro switches.

1. Installation Drawing of Knife Switch Micro Switches

△ Installation Schematic Diagram of Knife Switch Micro Switches (Double Confirmation of Knife Switch Position) in GIS Substations

2. Implementation Drawing of Knife Switch Micro Switch Sensors in Non-GIS Substations

3. Wiring Diagram of Measurement and Control Devices

Commissioning of the "One-Click Sequential Control" System

After the primary equipment is powered off, confirm whether the knife switch micro switches (double confirmation of knife switch position), remote signal, remote control circuits and other auxiliary conditions are normal. Conduct sequential control operations by bay according to the operation sequence of the switching operation tickets of the sequential control host (operation to hot standby, hot standby to operation, hot standby to cold standby, cold standby to hot standby). All these operations are performed by the sequential control host issuing commands to operate the primary equipment on-site. The sequential control operation of the bay is completed after confirming that the primary equipment is actually operated in place and the logic and signals are correct. Conduct sequential control commissioning of other bays in turn in accordance with this requirement.

Through the transformation of the "One-Click Sequential Control" system in smart substations, the transformation from traditional manual operation to automation and intellectualization has been realized, reducing manual operation items and operation time. It provides technical support for the development of smart power grids, staff reduction and efficiency improvement, and further enhances the intrinsic safety level of the power grid and power supply reliability.