Abstract:Modern substation systems exhibit relatively high operational stability, and the safety of equipment operation has been significantly improved. The application of unmanned substation operation and maintenance technology has played a crucial role in this process, serving as a key factor in enhancing the operational efficiency of modern substation systems. The article analyzes the application of unmanned substation operation and maintenance technology, clearly outlining its basic advantages and related issues, providing valuable experience for the application of this technology in unmanned substation systems.
Keywords:Unmanned; Substation; Operations and Maintenance; Mode
Introduction
In recent years, the gradual increase in demand for market electronic resources has led to the expansion of substation construction into complex environments. To ensure the stability of substation operations and the safety of personnel management, the application of unmanned substation technology is imperative. It is a crucial core solution to the issues of unstable operation of substation equipment and low efficiency in personnel and equipment management under complex conditions. The operation and maintenance technology models of unmanned substations are highly diversified. The application of technology should adhere to the fundamental principles of standardization and normalization to maximize the advantages of unmanned substation operation and maintenance technology in the substation system.
1. Current Operation Status of Unmanned Substation Mode
1.1 Advantages
(1) It facilitates scientific and rationalized personnel management. Unmanned transformer substations do not require 24/7 human supervision; the substation systems can operate autonomously with intelligent equipment. Traditional transformer stations heavily rely on personnel, making it difficult to organize standardized management in a short period. This hampers the workload and efficiency of relevant staff. In contrast, unmanned transformer substations fundamentally address this issue, alleviating the workload for technicians while enhancing the operational efficiency of the substation.
(2) Enhanced power supply safety and quality while reducing operational costs. The unmanned substation operates at a high level of intelligence and automation, boasting the ability to self-manage faults and allowing technicians to remotely operate it, achieving unmanned system control and ensuring the actual safety of substation management for technical staff. In terms of electronic technology, the unmanned substation operates with a comprehensive electronic system management, achieving networked operation through multiple computer terminals, which lowers the basic capital expenditure for regular equipment inspections. The operation status of substation equipment can be monitored simply through automated processing on computer networks, further enhancing the utilization benefits of substation equipment.
(3) The investment is low, and the construction period is shorter compared to other models. The operation of traditional substation systems requires significant personnel investment and, due to the complex construction environment of substation sites, gradual increases in equipment management investments are necessary. In the analysis of the 2016 funding for a specific substation, the cost for equipment maintenance and management alone reached over 1.3 million yuan, with labor costs totaling 420,000 yuan. The actual cost was 1.72 million yuan. In contrast, the operation of unstaffed substations can reduce labor costs, with annual consumption of only 90,000 yuan, and equipment maintenance costs of just 960,000 yuan. Compared to traditional substation operation, unstaffed substation operation incurs lower financial costs and simpler, more convenient construction.
1.2 Issues Identified
(1) There has been an increase in the difficulty of managing teams under the management level. While unmanned substations provide safety management guarantees for grassroots technical personnel and enhance the efficiency of equipment operation, they still lead to management chaos, particularly in personnel arrangement and allocation. Long-term placement of personnel in unmanned substations for related work results in significant waste of human resources. Although the operation of unmanned substation teams is highly mechanized, it still requires technical personnel to perform remote control within specified ranges, creating a conflict in personnel management that hinders proper team allocation.
(2) The tasks and positions assigned do not match the pressure-bearing requirements of the same team. Traditional substation operations are managed by a single team, whereas the current unmanned substation operations have reduced the workload for relevant technical personnel, and their actual management scope has gradually expanded. There are significant differences in technical equipment maintenance and management across different regions. This impacts the actual capacity of technical personnel, especially affecting the technical managers within the same team, increasing the difficulty of technical management. It often leads to situations such as unreasonable management arrangements and inadequate management for technical teams.
(3) The lack of a scientifically and reasonably arranged fixed personnel division. Although unstaffed substation operations have a lower dependency on personnel, they still require relevant technical and administrative staff to possess strong technical maintenance and management capabilities. Technicians with a certain level of management often face issues of aging, leading to relatively lower flexibility in operating modern electronic equipment; whereas young technicians lack strong technical maintenance and management capabilities. This further highlights the problem of personnel division, resulting in unscientific and unreasonable arrangements in personnel management across regions. The main issue with unstaffed substation operations stems from poor flexibility in personnel scheduling and utilization, making it difficult to organize equipment operation and maintenance work with technical personnel according to actual needs. As a result, actual work efficiency is hard to meet the expected standards for equipment operation planning, leading to a decrease in the operational benefits of unstaffed power stations.
(4) The current dispatch automation system at the control center has a single warning format. Photon brand and signal warnings are the primary methods of control for the dispatch center at this stage. This warning mode requires the relevant on-duty personnel to manually input warning information before equipment operation, which not only consumes excessive time but also delays equipment maintenance, preventing the equipment from being put into normal use in the short term. Due to insufficient understanding of warning signals by some personnel, the warning signal settings at substation locations in distributed areas often fail to serve their intended purpose, further leading to safety accidents and significantly reducing the operational safety of unmanned substations.
2. Solutions and Development
2.1 Establish a patrol inspection system to strengthen patrol inspections
During the implementation of unattended operation mode in substation, it is essential to minimize safety accidents and manage details meticulously. Compared to the traditional management model, the scope of authority for unattended units has changed. Therefore, on top of completing routine tasks, a comprehensive patrol and inspection system must be established to ensure its rules are suitable for the unattended operation mode.
2.2 Ensure the management and maintenance of substation equipment
The existing equipment in the unattended substation is no longer capable of achieving programmed and remote control operations. Some micro-computer protections lack the remote trip and reclose function, and some primary substation equipment still requires manual operation. To implement programmed operations, significant modifications to the existing operating procedures and typical operations are necessary. The equipment inspection in unattended substations is an important aspect of operation work. New technologies and equipment for auxiliary inspections can be considered to promptly identify equipment defects and greatly enhance the inspection effectiveness. The signal reset processing system for unattended substations is shown in Figure 1.
3. AcrelCloud-1000 Substation Operation and Maintenance Cloud Platform
3.1 Overview
The AcrelCloud-1000 Substation Operation and Maintenance Cloud Platform is a cloud-based management platform developed using technologies such as the Internet+, big data, and mobile communications. It meets the needs of users or maintenance companies to monitor the operating status and parameters of numerous substation circuits, indoor environmental temperature and humidity, cable and busbar operating temperatures, and on-site equipment or environmental video scenes. It achieves centralized storage and unified management of data, facilitating usage. It supports authorized users to access and receive alerts through various terminals such as computers, smartphones, and pads, and completes daily and regular inspection and dispatching of equipment management tasks.
3.2 Application Sites
New and expanded substation operation and maintenance systems for industries such as telecommunications, finance, transportation, energy, healthcare, culture and sports, education and scientific research, agriculture and water conservancy, commercial services, and public utilities.
3.3 System Architecture
The system is divided into four layers: the perception layer, transmission layer, application layer, and presentation layer.
Perception Layer: This includes multifunctional meters, temperature and humidity monitoring devices, cameras, and switch quantity collection devices installed at the substation. Apart from the cameras, the other equipment is connected to the site's intelligent gateway via the RS485 bus, with the RS485 port.
Transmission Layer: Includes field intelligent gateways and switches, etc. The intelligent gateway actively collects data from devices in the field equipment layer, performs protocol conversion, data storage, and uploads the data to the server port via the switch. In case of network failure, data can be stored locally and continued to be uploaded from the interrupted point when the network is restored, ensuring that data on the server end is not lost.
Application Layer: Includes the application server and database server. If there are fewer than 30 substation sites, the application server and database server can be configured together. The servers must have a fixed IP address to receive data actively transmitted by each intelligent gateway.
The Display Layer: Users can access platform information through multiple terminals such as smartphones, tablets, and computers.
3.4 System Features
3.4.1 Energy Consumption Monthly Report
The Energy Consumption Monthly Report supports users in querying the electricity usage of managed stations based on total electricity consumption, substation name, substation number, etc. The query span can be set to a monthly basis.
3.4.2 Site Monitoring
Site monitoring includes an overview, operational status, daily event logs, hourly electricity consumption curves for the day, and a summary of electricity usage.
3.4.3 Transformer Status
Transformer Status supports users in querying all or specific station transformers' power, load factor, and other operational status data, allowing for sorting in ascending or descending order based on load factor and power.
3.4.4 Operations
The Operations department showcases the current location and total information of transformer stations on the map for user management.
3.4.5 Power Distribution Diagram
The distribution diagram showcases the distribution information of the selected substation. It illustrates the switch states, current, and other operational statuses and information of each circuit, supporting detailed query of operating parameters such as voltage, current, and power.
3.4.6 Video Surveillance
Video surveillance displays the live feed, allowing you to select a specific substation transformer to view its video information.
3.4.7 Power Operation Report
The power operation report indicates that the selected equipment at the selected stations collects operating parameters and real-time as well as average values of electricity meters for each loop, performing statistics.
3.4.8 Alarm Information
Analyze all alarm information on the platform.
3.4.9 Task Management
The task management page allows for the posting of inspection or defect rectification tasks, viewing the status and completion of inspection or defect rectification tasks, and clicking to view specific task details for inspection information.
3.4.10 User Report
The User Reporting Page is primarily used for automatically summarizing a month's worth of operational data from selected transformer substations. It conducts statistical analysis of transformer load, distribution circuit electricity consumption, power factor, and alarm events, and lists various defects and their treatment found during inspections within this period.
3.4.11 APP Monitoring
The power operation and maintenance mobile app supports seven major modules: "Monitoring System," "Equipment Records," "To-Do List," "Inspection Records," "Defect Records," "Document Management," and "User Reports." It offers a range of functionalities including one-image, demand, energy consumption, video, curve, humidity and temperature, year-on-year, month-on-month, power quality, and various event alarm inquiries, as well as equipment records search, to-do event management, inspection record search, user report, and document management.
3.5 System Hardware Configuration
4. Closing Remarks
The implementation of unattended substation systems can further enhance the operational efficiency of power transmission systems and reduce the impact of human factors on their operation. Although the application of unattended substation operation and maintenance technology is somewhat complex, it plays a certain role in addressing operational faults and related technical issues within power transmission systems. Therefore, not only do we require technical personnel to fully grasp the key points and challenges of the technology, but also to conduct research on its advantages, facilitating the application of unattended substation operation and maintenance technology across multiple regional power transmission systems.
References
Wu Shihui. Operation and Maintenance Management Model and Application Analysis of Unmanned Substation. Communications World, 2016, (17): 152-153.
Zhong Zhun. Operation and Maintenance Technology Mode and Application of Unmanned Substation [A]. 2017.
[3] AnkoRui Enterprise Microgrid Design and Application Design, 2019, 11th Edition
