Summary: In September 2021, the National Development and Reform Commission issued the "Double Control Plan for Energy Consumption Intensity and Total Volume of Anshan Energy," which encourages the use of renewable energy and supports its development. Driven by such policies, the photovoltaic power generation market is undoubtedly poised to embrace new opportunities for high-quality development. Drawing on the daily management experience of the Shandong Museum photovoltaic power station and research on other projects, this article analyzes several prominent issues in the operation and maintenance process of the power station and offers solutions, hoping to enhance the quality of power station operations and promote the healthy development of China's solar power industry.
Keywords: Cultural Public Venue; Distributed Photovoltaic; Grid-connected Power Generation System; Operation and Maintenance Management
Introduction
In September 2021, the National Development and Reform Commission issued the "Scheme for Improving the Double Control System of Energy Consumption Intensity and Total Amount," proposing that by 2035, the optimized allocation and conservation of energy resources will become more mature and standardized. The "Fifteenth Five-Year Plan for Energy Development in Shandong Province" explicitly states that during the "Fifteenth Five-Year Plan" period, Shandong Province will implement a doubling action for renewable energy, promote the construction of rooftop photovoltaic systems on industrial buildings, commercial buildings, public buildings, and residential buildings, and prioritize the development of "self-generated and self-used" distributed photovoltaic systems. Driven by such policies, the photovoltaic power generation market is expected to embrace new opportunities for high-quality development.
The Shandong Museum's solar photovoltaic grid-connected power generation system is located on the top floor, covering an area of approximately 7,000 m². The photovoltaic array consists of 2,500 panels in 39 sets, each with a standard power of 180Wp, totaling 429kWp. The project was completed and put into operation in July 2010 and has been running continuously for 11 years to date. Based on the daily management experience of the power station and research on other projects, this article will discuss several issues that need attention during the daily operation and maintenance of photovoltaic power stations, aiming to enhance the operation system of solar power generation in cultural and public welfare venues.
1. Key Issues in the Operation and Maintenance of Grid-Connected Photovoltaic Power Stations
1.1 Lack of coordination and foresight in design
Based on the current level of distributed photovoltaic power generation systems, the design should comprehensively consider the actual conditions for implementation, such as hardware facilities and working environments, to plan the power station construction with a forward-looking perspective. This approach not only facilitates daily maintenance and management but also ensures the ability to integrate future advanced technologies. Over the 11 years of operation of the inverter at the Shandong Museum, the equipment within the机房 has functioned normally, while the outdoor equipment has undergone two major repairs. Evidence shows that an improperly designed location for the inverter, which is scattered around the site based on the unit division of solar panels, can inconvenience daily inspections. The harsh outdoor environment, with wind, sand, dust, and moisture, can easily enter the inverter, potentially causing internal circuit failures if protective measures are not taken. Mismatched or incompatible equipment selection and replacement can affect the system's power generation efficiency, posing safety and stability risks to the power grid.
1.2 Production and technical service levels are uneven.
Currently, solar photovoltaic power generation in our country has entered the commercial application stage. In terms of photovoltaic product production, market suppliers vary greatly in quality, with significant fluctuations in product quality; in terms of technical services, maintenance units have weak comprehensive capabilities, with varying skill levels among personnel, ultimately leading to various issues in the operation and maintenance management of photovoltaic power stations. During the initial construction phase of photovoltaic power stations, issues such as neglected design plans, defective equipment quality, and poor construction quality pose severe challenges to the later operation and maintenance; in daily management, engineers lack detailed understanding of the photovoltaic industry, have low professional ethics, and lack practical experience, leading to frequent technical failures due to improper operations or inadequate monitoring, which affects the normal operation of the photovoltaic power generation system.
Unclear division of responsibilities and management chaos between property owners and maintenance units.
A robust operation and maintenance management system is the foundation for the stable operation of power stations, and the solid execution of these systems is the reliable guarantee for their normal operation. The operation and maintenance management system for photovoltaic power stations primarily clarifies the management details in terms of operation and maintenance, defining the work responsibilities and handling authority of both the owners and maintenance units in the power station management. However, there are indeed issues of unclear rights and responsibilities and chaotic management in the current operation management of photovoltaic power stations: management interfaces between departments are blurred and even leave management gaps, the systems' rights and responsibilities are imperfect and unclear, leading to negative attitudes and procrastination from both owners and maintenance units; in terms of power station operation, data management, and maintenance, they often drag their feet. Some power stations have established relatively comprehensive operation and maintenance management systems, but there are shortcomings in personnel implementation, with laziness occurring from time to time.
1.4 Incomplete Asset Incentive Strategy
For a long time, the management and research of state-owned assets have primarily focused on the explicit investment returns, while the implicit and intrinsic returns of assets have not received sufficient attention. As a key project funded by the department, the development and utilization of renewable energy is often included in the overall operational budget during the unit's fiscal budget application, failing to reflect its distinctive importance. This leads to frequent issues in asset management, such as unclear performance assessment objectives, prioritizing use over management, budget being occupied, and low output效益. For profit-oriented photovoltaic power stations, a comprehensive study of the investment strategy, including operational models, management mechanisms, and policy support, has been completed from the perspective of investors. Similarly, the potential energy savings from the "self-production and self-use" model should also be promptly allocated for operation and maintenance funds, and actively explore asset incentive strategies for sustainable development.
2. Grid-connected Photovoltaic Power Plant Operation and Maintenance Management Recommendations
2.1 Optimized System Design Scheme
The cultural facility has a large floor area and an unobstructed roof, offering clear advantages for flat layouts, making it suitable for a rooftop distributed photovoltaic power generation system. The new facility's architecture and photovoltaic power generation system should be planned and designed as a unified unit, ensuring a harmonious and aesthetically pleasing exterior, as well as a safe and reliable power supply and distribution system. When implementing Building-Integrated Photovoltaics (BIPV) projects on existing buildings, structural modifications and electrical safety should also be taken into comprehensive consideration.
Based on the actual operating conditions of photovoltaic power stations, solar machine rooms are ideally situated on the building's roof or top floor, with control equipment centrally managed, optimizing the routing scheme, reducing line energy consumption, and minimizing fault points.
Inverters, as critical equipment in photovoltaic power generation systems, contain electronic components like capacitors and displays that are not heat-resistant. They should be centrally installed in machine rooms on the roof or top floor, providing shade from rain, protection from dust and moisture, and good ventilation for heat dissipation. The installation location should consider the distance between the network point and the components, with proximity to the network point saving investment costs and proximity to the components resulting in lower cable losses and easier construction. The support bases for battery arrays are often constructed using cast-in-place concrete methods. During the pouring process, it is recommended to add a suitable amount of waterproofing admixture to the concrete, designing and constructing it in conjunction with the roof waterproofing system to prevent any leakage issues from rainwater on the roof.
2.2 Select high-quality, cost-effective photovoltaic products and technical services
After more than a decade of development, China's photovoltaic manufacturing industry has achieved localization, with its industrial technology level and system construction reaching world-class standards. The production costs of polycrystalline silicon materials, solar panel components, inverters, and other products have significantly decreased. The vast market development prospects have also sparked industry contemplation: how to discern the quality of numerous photovoltaic products and ensure the lifespan and quality of power station operations.
The full lifespan of a photovoltaic power station spans over two decades, with the brand selection of key equipment and technical services being critical determinants of the station's profitability. Due to the exclusivity of technical patents, buyers should exercise caution in brand selection, screening the vast photovoltaic market with clear standards. They should consider factors such as brand influence, research and development capabilities, and the potential for enterprise development when choosing cooperation targets. Guided by market orientation, balancing cost control and performance enhancement, priority is given to brand enterprises with robust technical support and R&D investment, continuously improving their product quality, as long-term strategic partners.
Key factors affecting the power generation of distributed photovoltaic power stations include system efficiency. The selection or replacement of system components must comply with regulatory requirements. Sub-systems should be divided based on inverters, and the electrical performance parameters of components connected to the system should be as consistent as possible. For core products like solar panels, emphasis should be placed on photovoltaic conversion efficiency. For devices such as inverters, transformers, combiner boxes, and cables, which have relatively mature quality and technology, prioritize products with high cost-performance within the range of design parameters.
2.3 Develop and implement a detailed and feasible management plan
Cultural units should regularly organize studies on national new energy policies, keep pace with the development of the photovoltaic power generation industry, formulate long-term and medium-term plans for operation, maintenance, and inspection that align with the characteristics of their venues, and ensure effective management of power station operations.
Develop comprehensive and feasible management plans, with the fundamental task of ensuring the safety and integrity of state-owned assets. Not only should attention be paid to约束维保单位 and ensure operation and maintenance quality, but also the responsibilities and obligations of the property owners themselves must be clarified, and the enthusiasm and sense of responsibility for staff supervision and management should be strengthened. In terms of the overall management and maintenance of power stations, the state has successively issued a number of standards and specifications over the past decade, refined inspection cycles and maintenance rules, and standardized the informatization management of power stations.
The smooth operation of photovoltaic power stations requires regular maintenance. Maintenance units must analyze the service conditions of the stations, check for equipment running with defects, accurately identify the causes of failures, and determine the fault locations. Pay attention to the accumulation of dust and debris, loose contacts, and other issues within junction boxes and distribution cabinets. Inspect cable aging issues, monitor the thermal spot phenomenon on the solar panels, and understand the operation of inverter components. While conducting maintenance and management, record the real-time operational data of the station, such as weather conditions, generation time, power output, load status, and equipment malfunctions. Detailed and reliable maintenance records are the basic basis for determining whether the system is operating normally, aiding in system failure prediction, and allowing for timely formulation of response plans.
2.4 Enhance the Asset Incentive and Performance Evaluation System
Currently, China's main incentives for improving the energy efficiency of public buildings are financial subsidies. During the 14th Five-Year Plan period, photovoltaic power generation will achieve unsubsidized grid parity, and corresponding fiscal subsidy policies will gradually cease. Public building energy conservation and consumption reduction will face issues such as insufficient incentives. How to preserve and increase the value of photovoltaic power generation, and determine a scientific asset incentive plan, is an urgent matter.
Asset Incentives: While most property units focus on maintenance responsibilities for equipment, emphasizing safety and reliability, assets like photovoltaic power generation that utilize renewable energy for energy conservation and consumption reduction have the characteristic of hidden outputs, where equipment revenue is often overlooked.
The target of the asset incentive program primarily includes property rights units. On one hand, attention should be paid to the preservation of assets to prevent any loss. As public welfare institutions mainly rely on public finance, during the government's decision-making process on funding allocation, attention should be given to the financial applications for renewable energy development projects, and the funding for energy-saving and consumption-reduction projects should be allocated separately and prioritized. Adequate operation and maintenance funds are the prerequisite for the sustainable operation of the projects. On the other hand, efforts should be made to maintain the value-added nature of assets to ensure long-term stable economic benefits. For cultural and public welfare venues with the conditions and ability to achieve carbon neutrality, energy-saving and consumption-reduction should be incorporated as a main evaluation criterion or a bonus item in the annual performance assessment plan of the unit. Establish scientific performance incentive standards, quantify evaluation indicators, and make good use of rewards and penalties to enhance the guiding nature of asset incentives and promote the wider and deeper application of renewable energy in public buildings.
It is widely known that cultural venues are characterized by large building volumes and high energy consumption intensity. The adoption of photovoltaic power generation systems can achieve "self-generated and self-used" energy, alleviating part of the pressure on electricity load. Under sound policy incentives, property owners can obtain accurate feedback information from the actual operation and maintenance of the photovoltaic power generation system, identify gaps between objective facts and design intentions, derive lessons learned from both successes and failures, and form a project performance evaluation report, highlighting the hidden economic benefits of the equipment. The effectiveness evaluation is of great significance for the completeness and systematization of operation and maintenance plans, benefiting owners in analyzing management strategies from all angles, mobilizing and enhancing staff enthusiasm and sense of responsibility, continuously improving design concepts and energy-saving technologies; and promoting operation and maintenance companies to improve service quality, standardize staff behavior, avoid confusion in rights and responsibilities, and management chaos, thereby maximizing the socio-economic benefits of the photovoltaic power generation system.
3. AnkoRe Distributed Photovoltaic Operation and Maintenance Cloud Platform Introduction
3.1 Overview
AcrelCloud-1200 Distributed Photovoltaic Operation and Maintenance Cloud Platform monitors inverters, meteorological equipment, and camera devices at photovoltaic sites to assist users in managing their scattered PV sites. Key features include: site monitoring, inverter monitoring, power generation statistics, inverter one-line diagram, operation logs, alarm information, environmental monitoring, equipment files, operation and maintenance management, and role management. Users can access the platform via the WEB and APP to promptly grasp the efficiency and revenue of photovoltaic power generation.
3.2 Application Locations
Currently, China has two types of distributed application scenarios: household photovoltaic systems on rural rooftops and industrial and commercial enterprise rooftops. Both types of distributed photovoltaic power plants have seen rapid development this year.
3.3 System Architecture
Inverters and multi-functional power metering instruments have been installed in the photovoltaic substation. Data collected is uploaded to the server via a gateway and centrally stored and managed. Users can access the platform via PC to promptly obtain the operational status of the distributed photovoltaic power stations and the performance of each inverter. The overall structure of the platform is as shown in the figure.
3.4 System Functionality
The AcrelCloud-1200 Distributed Photovoltaic Operation and Maintenance Cloud Platform Software is based on the B/S architecture, allowing any authorized user to monitor the operational status of photovoltaic power stations across various buildings within the designated area through a web browser, based on their permission level. This includes information such as the geographical distribution of the power stations, station details, inverter status, power generation curve, grid connection status, current and total electricity generation, etc.
3.4.1 Photovoltaic Power Generation
3.4.1.1 Comprehensive Dashboard
●Display the number of photovoltaic power stations, installed capacity, and real-time power generation power.
Cumulative daily, monthly, and annual electricity generation and revenue.
Cumulative social benefits.
● Bar chart illustrates monthly electricity generation
3.4.1.2 Power Station Status
●The Power Plant Status showcases basic parameters such as the power generation capacity of the photovoltaic power plant, subsidy electricity price, and peak power.
●Monitor daily, monthly, and annual power generation and revenue from photovoltaic power stations.
● The camera monitors the on-site environment in real-time and integrates parameters such as illumination, temperature, humidity, and wind speed.
● Show the current number of photovoltaic power station inverters connected and their basic parameters.
3.4.1.3 Inverter Status
● Basic inverter parameters display.
● Display of daily, monthly, and annual electricity generation and revenue.
● Display inverter power and environmental irradiance curves through graphical charts.
Direct Current (DC) side voltage and current inquiry.
● Query for AC voltage, current, active power, frequency, and power factor.
3.4.1.4 Power Station Generation Statistics
● Display statistical reports of the selected power station's hourly, daily, monthly, and annual electricity generation.
3.4.1.5 Inverter Power Generation Statistics
● Display time, date, month, and year statistics of power generation for selected inverters
3.4.1.6 Power Distribution Diagram
● Real-time display of inverter's AC and DC side data.
● Display the current number of inverter connection components.
● Display current environmental parameters such as irradiance, temperature and humidity, and wind speed.
● Display inverter models and manufacturers.
3.4.1.7 Inverter Curve Analysis
● Display voltage and power curves for both AC and DC sides, as well as irradiance and temperature.
● Operation Log: User Login Status Inquiry.
● SMS Log: Check SMS push time, content, sending results, and replies.
● Platform Operation Log: Check仪表 status, gateway offline conditions.
● Alarm Information: Categorize alarm divisions for processing, record alarm content, occurrence time, and confirmation status.
3.4.3 Operating Environment
●Video Surveillance: With the installation of video cameras on-site, the operation of the photovoltaic station can be monitored in real-time. For cameras with hardware capabilities, recording playback and pan-tilt control functions are also supported.
The "14th Five-Year Plan for the Development of Renewable Energy" emphasizes leveraging the cost competitive advantage of renewable energy, adhering to the market-oriented approach, and prioritizing the development and utilization of renewable energy. As a new growth point in China's energy industry upgrade, the photovoltaic industry requires research on the operation and maintenance of distributed photovoltaic power generation systems to provide robust technical support for its scaled management. Relevant departments should strengthen management, improve power station operation quality, and promote the healthy development of China's solar power industry.
[Reference]
- Yang Rujun, Ma Yongling, Fan Zongqiang. Brief Discussion on Operation and Maintenance Management of Distributed Photovoltaic Grid-connected Power Generation System on the Rooftop of Cultural Public Venue [J]. Journal of Mechanical and Electrical Information, Issue 3, 2022.
- Zhan Zhengwang. Discussion on the Operation and Maintenance Management of Grid-connected Photovoltaic Power Stations[J]. China High-tech Industrial Development Zone, 2018(4): 126
- Ankorri Enterprise Microgrid Design and Application Manual. 2022.05 Edition
