solar PLANT MONITORING TECHNOLOGY
operation & maintenance
OPERATION AND MAINTENANCE
Compared to other power generating technologies, solar PV power plants have low maintenance and servicing requirements. However, proper maintenance of a PV plant is essential to maximise both energy yield and the plant’s useful life. Optimal operations must strike a balance between maximising production and minimising cost. The presence of an operation and maintenance (O&M) contract is crucial to define the parameters for the operation and maintenance of a project during its life. If an O&M contractor is being employed to undertake these tasks, it is important that all requirements relating to preventative and corrective maintenance, performance monitoring and reporting are clearly stated in the contract along with the frequency with which these activities need to be conducted. This allows contractor performance to be measured and if necessary challenged. It is normal for an O&M contractor to guarantee plant performance during the contract term. Typically this is achieved through the presence of an availability- or performance-ratio warranty covering the entire plant. In the event of the contractor not honouring its obligations, resulting in the plant performing below the guaranteed value, the owner would be eligible to claim for compensation to cover lost revenues
A monitoring system is an essential part of a PV plant. Monitoring devices are crucial for the calculation of liquidated damages (LDs) and confirmation that the EPC contractor has fulfilled its obligations. Automatic data acquisition and monitoring technology is also essential during the operational phase in order to maintain a high level of performance, reduce downtime and ensure rapid fault detection.A monitoring system allows the yield of the plant to be monitored and compared with theoretical calculations and raise warnings on a daily basis if there is a performance shortfall. Faults can therefore be detected and rectified before they have an appreciable effect on production. Without a reliable monitoring system it can take many months for a poorly performing plant to be identified. This can lead to unnecessary revenue loss. The key to a reliable monitoring and fault detection methodology is to have good simultaneous measurements of the solar irradiance, environmental conditions and plant power output. This is achieved by incorporating a weather station on site to measure the plane of array irradiance, module and ambient temperature, and preferably global horizontal irradiance, humidity and wind speed.The performance of a PV power plant may be optimised by a combination of several enabling factors: premium modules and inverters, a good system design with highquality and correctly-installed components and a good preventative maintenance and monitoring regime leading to low operational faults.