SOLAR INVERTERS
SOLAR INVERTERS
DETAILED ANALYSIS AND LEARNING FROM O & M REPORT OF 590 MW PV PLANT IN GOLMUD: IMPORTANCE OF SELECTING PV DEVICES
In the recent two years there has been tremendous decrease in prices for solar plant equipments as well as solar power tariff. Solar community is debating on quality and selection of right equipments to work on Levelised cost, instead of only initial CAPEX.
During the 25 years of service life of a PV plant, the only way to maximize the PV system benefits is to reduce the Levelised cost of electricity( LCOE).
sum of costs over lifetime LCOE = sum of electrical energy produced over lifetime
T otal cost of a PV plant in its lifetime = Total initial investment + O & M cost – Salvage value of the system. Considering that the cost of PV devices occupies a part of the initial investment on a PV plant, the plant will be faulty once a device fault occurs. What is more, if the device vendor goes bankrupt, after-sales O & M for the plant cannot be ensured. This not only increases the O & M cost, but also weakens the overall benefits of the PV plant.
So what are the factors for selecting PV devices? Huanghe Hydropower Development Co., Ltd.( Huanghe for short) shared the major device faults and O & M experience on the 590 MW PV plant in Golmud for your reference.
Golmud in Qinghai is rich in light resources. It is the area with the best lighting condition in China in addition to Lhasa. Since 2011, Huanghe started to construct a 590 MW PV plant in Golmud. The plant occupies 14.62 km2 and is divided into five stages. The first stage of the PV plant connected to the power grid and started to generate power in 2011. The fifth stage of the PV plant connected to the power grid and started to generate power in June 1, 2016.
As the PV plant is located in the Gobi Desert with harsh environment such as fierce wind and sandstorm, occupies a large area, and has a great deal of equipment, challenges exist in the monitoring, inspection, and troubleshooting of the plant. The high fault ratio, routine inspection, and replacement of devices are the difficulties in O & M. inverters and string inverters. The practical O & M shows that faults are found on both the AC and DC sides. AC faults occur less frequently and mainly relate to cables, boxtype transformers, civil work, and step-up transformers. They account for 9.82 % of total faults. DC faults occur more frequently, are not easily to be found, and mainly relate to PV modules, inverters, and combiner boxes. They account for 90.18 % of total faults.
According to Shi Tianze, General Manager of the Haixi New Energy Yield Dept, Qinghai Huanghe Hydropower Development Co., Ltd., the 590 MW PV plant in Golmud uses both central
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EQ December 2016 www. EQMagPro. com