Summary: The power system holds application value within power enterprises. As the scale of the power system expands and the application volume of power equipment increases, considering the current operation of the power system and the growing electricity generation, relevant units need to enhance the application of substation operation and maintenance technology to ensure substation operational benefits. To this end, the existing substation operation and maintenance systems should be improved. The research now focuses on how to utilize substation operation and maintenance techniques in new power systems.
Keywords: Substation Operation and Maintenance Technology; Power System; Application Methods
Transformer systems are a key component of modern power transmission, using transformer equipment to transmit electrical energy and control voltage in the lines. Power companies often form specialized transformer operation and maintenance teams to oversee the power system and ensure electrical safety. While automated transformer systems are in use, maintenance work remains crucial. The power system often harbors various potential hazards, so power companies should ensure the continuity of power supply and other power production tasks through timely transformer operation and maintenance.
1. Overview of Substation Operation and Maintenance Work
The substation operation and maintenance management primarily revolves around various substation facilities used in the power system, including switching operations, power interruption and restoration, etc. The superior organizational bodies should utilize the substation operation and maintenance system to ensure the standardization of power control and management. The composition of daily substation operation and maintenance work is complex, differing significantly from conventional power control and management activities.
The duties of substation operation and maintenance are complex, primarily responsible for maintaining unattended substation facilities, handling accidents in substation operations, inspecting various power equipment, and ensuring that power enterprises adopt a civilized power production model. There is a large number of diverse equipment under inspection in the substation system, with varying maintenance requirements; the work content of substation operation and maintenance is fixed, making it rather monotonous, and operation and maintenance personnel are prone to fatigue in mechanized and technical management tasks. When substation equipment malfunctions, it is difficult to locate the issues, and the workload for equipment inspections is substantial, making it impossible to manage substation equipment centrally quickly. The conditions for building an information management system are poor, and the use of information systems at substation operation and maintenance workstations is challenging. The quality of substation operation and maintenance work is continuously affected by technical personnel, and power enterprises have not systematically trained operation and maintenance staff. They are unfamiliar with new substation equipment, making it difficult to implement substation management during operation and maintenance tasks.
2. Primary Causes of Transformer Substation Operation and Maintenance Failures
2.1 Objective Factors
Transformer equipment in power systems often operates for extended periods, making it more susceptible to aging due to operational conditions. Once aging occurs, various aspects of the equipment's performance may be compromised, leading to an increased frequency of malfunctions. With the rising demand for electricity, the lines and equipment in the power system must bear greater power loads, leading to neglect of routine maintenance management. Under the influence of usage demands, the equipment's damage rate is also elevated, resulting in frequent malfunctions. Some power equipment is prone to be affected by adverse weather conditions; after thunderstorms, power supply systems may experience interruptions. These objective factors increase the workload for transformer operation and maintenance management.
2.2 Human Factors
Human factors are the primary cause of frequent transformer operation and maintenance failures, which can be categorized into the following three aspects: 1) Lack of strong safety management awareness among transformer operation and maintenance management personnel, who do not prioritize the management of transformer operations, fail to regulate related activities, and lack adequate supervision, ultimately affecting the quality of transformer operation and maintenance; 2) Many power companies fail to implement various management systems, coupled with the absence of a comprehensive work assessment mechanism, leading to many management systems being ineffective and creating a chaotic management situation; 3) Despite long-term management efforts, many power companies, although they repeatedly summarize common failures, most do not establish a sound prevention system.
Specific Applications of Substation Operation and Maintenance Technology in the Power System
3.1 Addressing Triple-Sided Switch Power Fault
The power outage situation here is complex and variable. The maintenance staff must first confirm the usage of the oil tank and strictly prohibit any oil leakage.
Thoroughly inspect the secondary circuit; determine whether the tripping of the switch is caused by a secondary circuit fault or a main transformer fault. Upon identifying a fault within the main transformer's oil tank as the cause of the protective action, report it immediately to the on-duty dispatcher. Place the faulty main transformer in cold standby mode, and after relevant maintenance personnel have addressed the issue, resume operation only after the fault is resolved. Prior to identifying the cause of the fault, the main transformer must not be put into operation. If a differential protection action occurs in the main transformer, the substation operation and maintenance personnel should inspect the electrical equipment located after the CTs on both sides of the main transformer, including the CTs on both sides, switchgear, busbars, transformer bushings and leads, as well as the transformer PT and surge arresters on both sides. If a specific device on one side of the main transformer is found to be the cause of the differential protection action, report this situation to the on-duty dispatcher immediately, place the faulty main transformer in cold standby mode, and only resume operation after the fault is resolved by maintenance personnel. If the main transformer experiences zero-sequence overvoltage protection, the substation operation and maintenance personnel should determine which side has experienced zero-sequence overvoltage and inspect the transformer's bushings and leads on that side. If the fault is due to grounding of the main transformer or one of its leads, or if the main transformer can operate normally while the system is not, appropriate actions should be taken under the guidance of the dispatching command.
3.2 Addressing Power Faults in the Processing Line Switch
Transformer circuit breakers often experience faults, primarily tripping issues. Operations personnel should first determine the circuit fault, identify the power line with the fault, and then arrive at the circuit breaker of the tripped line. Conduct a rigorous analysis of the breaker's action reports, combining fault wave recording data. After analysis, compile a line fault investigation report and submit it to the power dispatch personnel. Inspect the transformer equipment involved, continue to report inspection information, and proceed with fault handling according to the dispatcher's instructions. Inspect the circuit breakers and carry out necessary electrical maintenance work.
3.3 Addressing Power Fault in Main Transformer Low-Voltage Switch
If a current protection trip occurs on the low-voltage side of the main transformer in the power system, the line should be inspected to diagnose the specific type of power fault. If the line does not exhibit a failure to operate, the fault may be in the busbar system. In this case, inspect the busbars in use on the line and the switchgear, determining the cause of the power fault before reporting the situation to the power dispatch and following dispatch instructions to complete the work. Line switches may also fail to operate when applied, so the inspection should shift to the secondary circuit system to identify issues like burnouts, broken wires, and poor contacts. Many control circuit faults are caused by secondary circuit problems. If all equipment in the line is tested and the fault type and cause are not confirmed, the busbar system should not be directly restored for normal power supply activities. Only after identifying the fault and performing necessary isolation can the busbar be restored to reduce the impact on the power system. In cases where a low-voltage side switch trips due to a failure-to-operate phenomenon, the failed switch should be isolated first, determine the status of the busbar equipment, and if there are no other anomalies, apply for power dispatch handling. The power supply at the failed switch location cannot be restored.
3.4 Install Grounding Lines
During the installation of grounding lines, technicians must determine the usage of excess voltage. After introducing excess voltage into the underground system, they should monitor the connectivity of the lines to ensure a safe and stable operation of the power system. The work of installing grounding lines should be conducted correctly, avoiding any sudden circuit connections. They should measure the actual static induction voltage of the equipment in the line system. When maintenance personnel inspect the grounding system, they must wear insulating gloves to prevent electric shock accidents. During the installation of isolating switches, the entire process should be supervised to prevent safety incidents.
Transformer Substation Operation and Maintenance Management Measures
4.1 Implementation of operation and maintenance management for substation equipment
The operation and maintenance management of substation equipment is crucial, directly impacting the ultimate work efficiency of power enterprises. To ensure the continuity and reliability of power supply, the level of current substation operation and maintenance management needs to be further enhanced. Maintenance personnel must conduct necessary regular inspections and also pay attention to detailed technical issues during daily patrols, maintain power equipment, and minimize errors in the operation and maintenance management process. After the launch of the automatic operation and maintenance management system, there should be no arbitrary handling of operation and maintenance management tasks. Ground fault issues should be addressed, and work records should be kept during shift handovers.
4.2 Strengthen the management of record books
The ledger system supports substation operation management, and the use of the ledger control system can help enhance the efficiency of substation management. The reliability of the substation system is also strengthened with the intervention of ledger management methods. Most power companies have implemented a refined power control and management plan, expanded the construction of the power supply system, added numerous safe power equipment, and upgraded existing equipment. By inspecting and finding out equipment that has shown signs of aging, all changes in equipment during the substation control operations should be recorded.
Clear documentation and proceed under the guidance of technical specifications. Utilize the Substation Information Management System to provide necessary support for maintenance operations management. After entering equipment replacement and maintenance information, it enables more efficient arrangement of substation control and management tasks.
Ankorri Substation Operation and Maintenance Cloud Platform
5.1 Overview
The AcrelCloud-1000 Substation Operation and Maintenance Cloud Platform is a cloud-based management platform developed based on technologies such as the Internet+, big data, and mobile communications. It meets the needs of users or operation and maintenance companies to monitor the operating status and parameters of numerous substation circuits, indoor environmental temperature and humidity, cable and busbar operating temperatures, as well as on-site equipment or environmental video scenes. It achieves centralized storage and unified management of data, facilitating use, and supports authorized users to access, receive alarms, and complete daily and regular inspection and dispatching management tasks through various terminals like computers, smartphones, and pads.
5.2. Application Locations
New and expanded power distribution 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, public utilities, and electronic industrial parks.
5.3 Platform Structure
A smart gateway has been installed in the substation, collecting data from intelligent equipment within the substation. After protocol conversion and compression encryption, the data is uploaded to the platform at scheduled intervals or triggered uploads. The platform facilitates data exchange among all intelligent devices in the substation, enabling real-time monitoring of the operating status of critical equipment such as transformers and circuit breakers. It also monitors the operational data and environmental temperatures of various circuits within the substation. The communication management unit connects to the factory's local area network, transmitting data to the data center.
The AcrelCloud-1000 Substation Operation and Maintenance Cloud Platform offers functionalities such as user overview, power data monitoring, power quality analysis, energy consumption analysis, monthly, daily, and annual energy consumption data reports, alarm and record of abnormal events, operating environment monitoring, equipment maintenance, user reports, and operation and maintenance dispatching, while supporting multi-platform and multi-terminal data access.
The AcrelCloud-1000 Substation Operation and Maintenance Cloud Platform System is divided into four layers: the perception layer, transmission layer, application layer, and display layer.
The感知layer includes multifunctional meters, temperature and humidity monitoring devices, cameras, and switch quantity collection devices installed at the substation. All devices except the camera are connected to the on-site intelligent gateway via the RS485 bus, with the RS485 port.
Transmission Layer: Includes on-site 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, the data can be stored locally and continued to be uploaded from the interrupted point once the network is restored, ensuring that the server end does not lose any data.
The application layer includes the application server and the database server. If there are less than 30 substation sites, the application server and the database server can be configured together. The servers must have a fixed IP address to receive data actively transmitted from each intelligent gateway.
The Display Layer: Users can access platform information through various devices such as smartphones, tablets, and computers.
5.4 Platform Features
5.4.1 Real-time Monitoring
A single click on the distribution circuit allows for viewing detailed electricity consumption data, generating power operation reports, and querying historical data for various electrical parameters, voltage, current, power, harmonics, and environmental data monitoring.
May 4th, 2023 Energy Consumption Report
The Energy Consumption Monthly Report supports users in querying the electricity usage of their managed stations by total electricity consumption, substation name, substation number, etc., with the query range settable to monthly.
5.4.3 Site Monitoring
Site monitoring includes an overview, operational status, daily event logs, hourly electricity usage curves for the day, and a summary of electricity consumption.
5.4.4 Transformer Status
Transformer Status supports users in querying all or specific station transformers' power, load factor, and other operational status data, with the capability to sort by load factor and power in ascending or descending order.
5.4.5 Power Operation and Maintenance
The Operations team showcases the current location and total information of substation users on the map.
4.5.6 Power Distribution Diagram
The distribution diagram showcases the power distribution information of the selected substation. It illustrates the switch states and operating conditions such as current for each circuit, and supports detailed query of operating parameters including voltage, current, and power.
5.4.7 Video Surveillance
The video surveillance displays the live feed. Select a substation transformer, and you can view the video information within it.
5.4.8 Electric Power Operation Report
The power operation report shows the real-time and average values of the operation parameters and electricity meter readings for each loop of the selected equipment at the selected station, with statistics performed on the collection intervals.
5.4.9 Fault Alert
Remote Monitoring and Alarm (web and SMS), with adjustable alarm upper and lower limits, for substation operating environments (water immersion, smoke, etc.) alarms
5.4.10 Task Management
The task management page allows for the posting of inspection or defect rectification tasks, viewing the status and completion of these tasks, and clicking to view specific task details for inspection information.5.4.11 User Report
The User Reporting Page is primarily designed to automatically summarize one month's operational data for selected transformer substation configurations. It conducts statistical analysis of transformer load, distribution circuit energy consumption, power factor, and alarm events, and lists various defects found during inspections within this period, along with their treatment status.
5.4.12 Mobile APP
3.12 The APP supports the "Monitoring System," "Equipment Archive," "To-Do List," "Inspection Record," "Defect Record," "Document Management," and "User Report" modules for power operation and maintenance on mobile devices. It offers functionalities such as one-image display, demand, electricity consumption, video, curve, temperature and humidity, year-on-year and month-on-month comparisons, power quality, and various event alarm queries. It also includes equipment archive search, to-do event management, inspection record review, user report, and document management.
Conclusion
Most power companies have shifted their original business philosophy, focusing on the actual returns of power production while also examining and enhancing the overall safety of the power system. Based on the previous power management work, they have elevated the level of operation and maintenance. This ensures that various equipment issues within the power system can be detected in time, repaired, or replaced immediately, and fault issues can be resolved relatively quickly, maintaining a stable and long-term operation of the power system. In summary, during the new era of power development, substation operation and maintenance personnel should leverage automation technology to improve operation and maintenance management efficiency.
Reference
[1] Dong Jiaxi, Liu Meng, Application of Substation Operation and Maintenance Technology in the Electric Power System
Yang Lei. Application Analysis of Equipment Status Maintenance Technology in Substation Operation and Maintenance. China Strategic Emerging Industries, 2017(40): 183.
[3] Corporate Microgrid Design and Application Manual. 2020.06 Edition.
[4] Ankoray's User Substation Integrated Automation and Operation & Maintenance Solution, Version 2020.05.
