Last month, major Chinese PV plant investor and operator Huanghe Hydropower Development Co. made a major claim about one of its projects. In a press release the company said one of its recently finished and connected PV power plants is the most advanced smart PV power plant ever built by the industry. Combined with both hard and software from Huawei and Millennium software, which are two smart system technology providers, the plant can be controlled, managed and operated remotely and the operation cost can be reduced greatly compared to a conventional PV power plant.
The concept of a smart PV power plant (or intelligent PV power plant) management system is not new to the industry, but it is becoming increasingly popular in China. While various views exist as to the merits of smart power plants, they are clearly being built and intelligence is being retrofitted to existing plants.
The fundamental and perhaps most important driving factor in customers deciding on smart systems is their ability to deliver increased power generation and lower O&M costs. Based on calculations by Huawei Technologies, the power generation output of the PV power plant that employs smart technology is 3% to 7% greater when compared to conventional technology. The direct cost of O&M will drop by up to 50%, claims Huawei, with the major savings coming from labor costs, which are gradually rising in China.
What is a smart PV plant?
Since no consensus exists for what is precisely meant by a smart PV power plant, different perspectives are worth considering.
Traditional software vendor: Vendors of traditional control systems to power plants believe that new smart control systems are more like an upgrade on existing systems. The control system is always one of the most important parts of a power plant, whether it is a solar PV plant or not. There are three fundamental parts of a traditional control system.
The basic control system employs IT to calculate power production predictions, in line with the requirements of the grid. The data analysis system then collects and consolidates production data for management analysis. By utilizing both program redesign and modification or deployment of new hardware, an upgraded system will collect more data, make further calculations, and analyze more deeply prediction and output information to increase response accuracy to management requirements. But generally speaking, the smart control system is treated as an expansion of the data analysis system.
Inverter manufacturer: While some other vendors believe smart systems should be more than simply a control system, Chinese inverter manufacturer Sungrow Power jointly with Aliyun (which is powered by Alibaba) launched a new product called iSolarCloud as an online management platform for any plant operators interested in employing the system.
The iSolarCloud, as its name implies, uses cloud computing to allow remote control of a plant. Moreover, it enables comparison with other users key indicators such as power generation efficiency and average failure rate (FR), to figure out the weak points of a plants O&M or components. The focus on cloud computing makes it closer to the concept of Internet+, a mixture of Internet, cloud computing, big data and the Internet of Things. This excites some but frightens others, particularly those who are concerned about the security of their operational data. Is the cloud safe? Will data be exposed to competitors? The operators of the cloud solution have to answer many questions before customers become more comfortable.
xAdvertisementICT entrant: While not as radical as the Clouders, Huawei, is a new entrant to the PV industry from ICT, having joined the solar industry four years ago. Huawei believes the smart system for PV power plants first of all is a control system, but beyond that, it should be a control system redefined from an information communications technology (ICT) viewpoint. From the perspective of ICT, information from different levels will be gathered, transferred, consolidated, and interacted with on an information platform. Analysis is available based on data mining for a range of management requirements.
To realize the main features of the system, data accuracy and high speed intranet are the two key requirements, which are both strengths of Huawei. Known as the giant of wireless communications technology, Huawei says it has delivered competitive advantages from its experience working with computer chips to algorithms of short-range wireless communication.
Based on its own HiSilicon chip, Huawei specially designed and manufactured sensors to be integrated into string inverters for solar applications with high sensitivity for data collection.
We believe the string inverter is the key component of the whole system and all information required comes from string inverters, said Yingtong Xu, GM of Huawei Smart PV Plant Solutions. With higher and higher efficiency of the string inverter, it can be used on not only small-sized distribution PV plants, but also huge-sized ground-mounted PV plants. The recently completed Golmud projects of Huanghe Hydropower, with a capacity of 200 MW, incorporated string inverters from Huawei.
Benefits of a smart PV plant
The vision of the smart PV plant, managed by a Huawei inverter, is as follows: A park operator is sitting in an air-conditioned central control room, watching big screens that show multiple solar PV plants. The information on screen from the smart system is based on live electrical data collected from thousands, maybe more, of string inverters on site. And meanwhile the controller can switch the screen views to almost any site that he or she is interested in via video cameras installed on site.
If a fault is detected, the operator can easily search and locate where the failure is. A maintenance engineer on site can then be called to check or confirm the fault. Because the operator knows the exact place of the fault, the engineer does not need to drive and patrol for a whole day to find the problem. When the engineer arrives at the point of the fault, they then may require a little more help from the operator. This is remote diagnosis and problem solving in action.
In the meantime, a programed UAV can be accurately flying through a designed route to patrol the whole plant. Airborne infrared cameras will take an image of each PV module and mark those with abnormal reflection areas for the maintenance teams reference. The team can then replace any module that is performing below standard.
Active tracking cameras installed on the perimeter and also inside and throughout the plant act as watchdog. Any unauthorized entrants will be followed and recorded by these cameras. If an intruder is detected, the smart system will display the entrant on screen, alerting the site guard to the individuals presence.
These tools are all based on 4G LTE and Bluetooth communications systems deployed on site, which provide high speed broadband for intranet to connect all equipment including string inverters, box-type transformer substations, digital camera wireless handheld terminals, UAVs, and personal cell phones and apps. With the interaction of all of the information sources from the various pieces of equipment, problems can be transferred to relevant teams as quickly as possible and the centralization of operational resources increased to deliver resource efficiency and reduce costs.
In addition, major parts in the smart plant system can be upgraded with more modern replacement components, in order to realize better performance. For example, robotic cleaning technology could possibly be added into the system to significantly reduce cleaning costs, but only subsequent to an analysis determining that the technology would enhance the plants economic and technical performance.
As for the cloud computing in this area, Huawei does not believe that data mining and analysis is problematic. Based on more accurate data collected from high-accuracy sensors in string inverters and transferred through high speed on-site intranet, the system can provide more accurate conclusions and suggestions for the plant operators reference.
Only with more accurate data can this system provide our customers with more precise reporting and advice, said Huaweis Yingtong Xu.
It should be noted that adding intelligence to PV power plants does not come without cost, and in competitive bidding processes it could be an aspect that falls by the wayside. The suitability of hardware in the field for long periods of time may also cause developers to hesitate. Nonetheless, the market is growing.
About 50% of the PV plants finished in China since 2014 are smart or at least utilize some of the smart technology, according to Huawei. The ratio is lower outside of China. This may well be because most projects in China are on a larger scale, so utilizing a smart system benefits investors and operators more. For already established and operational PV plants, some are seeking opportunities to retrofit to smart systems, the obstacle being whether they considered the systems scalability at the very beginning and chose the corresponding hardware.
A different business model may become a future trend. The owners of the PV power plant asset could contract its operation to a service provider that can operate dozens or even hundreds of power plants via a cloud platform. While providers of this type of service are more common in Europe and North America, it is only in its early stages in China. It is indeed the direction in which some smart system suppliers in China are currently focusing their efforts. Calculations based on the current enhanced 17.8 GW installation plan by the government shows by the end of 2020, O&M costs of the entire solar PV plant fleet in China will grow to CNY 64 billion ($10.3 billion): an outsourced operations market at which service providers are looking closely.
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