Guodian Zhongwei Xuanhe Phase I 20MWp Photovoltaic Grid-connected Power Station Power Monitoring System

Project Description:

Ankerui Electric Co., Ltd. undertook the State Power Zhongwei Xuanhe Phase I 20MWp PV grid-connected power plant power monitoring system project in November 2011. This project is built in Xuanhe, Zhongwei, Ningxia. The site is 1300m-1350m above sea level with an installed capacity of 20MWp. The entire system adopts Acrel-2000V8.0 photovoltaic power station power monitoring system to complete real-time monitoring, analysis and control of the equipment such as battery arrays, combiner boxes, inverters, and AC/DC power distribution cabinets in photovoltaic power plants.

The project adopts block-based power generation and centralized grid-connected schemes, and divides the system into four 5MWp grid-connected power generation systems. After the four power subsystems output 35kV, they are sent to the grid through a 35kV power distribution room connected to the grid. The solar cell module is fixed with 20MWp, one inverter chamber is built for each 1MWp, and the array of 20MWp solar cell modules is composed of four 5MWp power generating units. The entire photovoltaic power station is equipped with a total of 38 sets of 500kW photovoltaic grid-connected inverters without isolation transformers and four 250kW inverters without isolation transformers, all of which are arranged in the inverter room. The inverter of this project adopts the operation mode of single-click automatic grid-connection. That is, when an inverter of any one of the inverters meets the inverter startup requirements when the voltage and power of the solar cell module meet the inverter startup requirements, the inverter is automatically put into operation.

The State Power Zhongwei Xuanhe Phase 1 grid-connected power generation project adopts a hierarchical ring network structure. The system uses a fiber-optic ring network structure. A 35kV switch station deploys a communications management machine and is directly connected via Ethernet. Each photovoltaic monitoring subsystem adopts a communication management machine to communicate with the smart devices in the station. The system accesses all on-line monitoring equipment of photovoltaic power plants through the communication management machine to conduct unified management of the equipment and collect, view and analyze the equipment operation data.

The main functions of the system:

1. Monitor the operating conditions of the string parameters (current, voltage, temperature, switch) of the DC bus monitoring box.

2. Realize the independent measurement of the PV string current and alarm the faulty PV string.

3. Connect the outdoor weather station's radiation value, temperature, and wind speed data and perform calculations.

4. Monitor the operating status of the inverter. Use the sound and light alarm to indicate that the equipment is faulty. Check the cause of the fault and the fault time.

5. Monitor the status of the high-side switch of the box transformer, monitor and remotely control the operating status and parameters of the dual-axis tracking device.

6. Real-time display of the power station's current total power generation, cumulative total power generation, total CO2 emission reductions, and daily power generation curve.