Jingsheng Huang

Design and development of movable testing platform for photovoltaic power station connected to low-voltage distribution grid

State grid corporation of China(SGCC) has issued “Technical rule for PV power station connected to grid (trial)” in July 2009, while claimed that grid-connected testing would be accepted and adopted if the PV power station connecting to the grid. According to the technical rule for PV power station connected to grid, a type of movable field testing platform for low voltage distribution grid-connected PV power station has been developed. This platform can complete the field testing for PV power station, including voltage/frequency response features, anti-islanding protection properties, power output features, power quality indicators and the other general performance indicators. Considering the developing feature of small-scale PV station and traffic condition in China, the platform has been designed for anti-seismic, anti-noise, anti-heat, anti-fire, anti-collision, anti-static and anti-electromagnetic interference, reaching to IP65 protection level. This platform has tested one PV power station, depending on the testing results from the platform testing, then all the anticipatory testing contents could be accomplished.

Study on power generation of PV station under shadow effect of ultra high voltage tower

In this paper, a photovoltaic station which local in Yancheng, Jiangsu province with installed capacity 19MW as an example to analysis the output of PV station which effect by the shadow of (ultra high voltage) UHV tower. Firstly, the model of UHV tower is established, the shadow range of UHV tower on winter solstice day is calculation according to local latitude and longitude information combined with the method of sun position calculation. Secondly, according to the location of UHV tower placed in PV station and the number of UHV tower, the range of UHV tower shadow which effect the PV station is analyzed. Based on these analysis, the change of annual power generation of PV station which before and after the effect of UHV tower shadow is simulated. The results shows that, this PV station which installed capacity is 19MW will be loss 139593kWh power generation per year by the effected of UHV tower shadow. The simulation results can provide some suggestions for the PV station and UHV optimization design.

Uncertainty evaluation of European efficiency in Photovoltaic inverter

In order to evaluate the accuracy of the European efficiency measurement result in Photovoltaic inverter, the uncertainty evaluation of European efficiency in Photovolatic inverter is searched in this paper. According to the standards of EN50530-2010 “Overall efficiency of grid connected photovoltaic inverters” and CNAS-GL08 “Guidance on evaluating the uncertainty in electrical apparatus testing”, the class A uncertainty of test results and class B uncertainty of testing equipment are evaluated. Based on this, the European efficiency is evaluated according to the calculation formula of inverter efficiency and European efficiency. The evaluation case indicated that the uncertainty evaluation method has practicality.

Steady-state control performance modeling and simulation analysis for grid-connected PV inverter

Because photovoltaic (PV) power generation has characteristics of volatility and randomness, with large-scale PV power generation connected to the grid, it will effect the safe and stable operation of power gird. It is necessary to establish an accurate grid-connected PV inverter model to carry out a reliable load flow analysis calculations. Under the steady-state, grid-connected PV inverter control performance mainly includes the maximum power point tracking (MPPT) control, active power set point control, active power reduction control with increases in grid frequency, reactive power control, protection control, etc. In the paper, using DIgSILENT/ Powerfactory software to establish a 500kW three-phase grid-connected PV inverter model. The PV inverter model can give expression to the steady-state control strategy, carried out simulation analysis according to different control modes. The paper verifies the accuracy of the PV inverter model, combined with laboratory type testing data.

Modeling and performance assessment of PV plants based on field-test of power generation unit

PV power plants should meet technical requirements before connected to grid. Due to the equipment capacity and cost constraints, low voltage ride through (LVRT) of the plants can not be directly tested. In this paper, the methods to assess PV plants performance based on the field test of power generation unit (PGU) are introduced. At first, the way to test LVRT capability of PGU is put forwarded, and then modeling and model correction is developed with t DIgSILENT Power- Factory. After the correction of PGU model, the whole PV plants model is built, including a mount of inverters, transformers, PV arrays, cabbles and other key components. The LVRT performance of PV plants is evaluated by the simulation result.