Project background
There are 1526 sets of bus boxes in a project in Qinghai. The insulation of the components in the bus boxes is aging, and due to the high temperature in summer and AGC's frequent load regulation, the current fluctuates greatly, resulting in frequent burning loss. Moreover, the communication detection unit inside the bus-box often fails to communicate with the background and can not monitor the running status of the equipment in real time. As a result, the failure of the bus-box cannot be found in time, which affects the normal management of the power station and the power generation efficiency.
Transformation goal
Replace the existing 1526 bus-box monitoring modules with split measuring modules (the number of branches measured by the split measuring modules should not be more than 4 channels), replace the communication equipment with an all-in-one communication power supply machine, and complete the communication transformation of the bus-box to ensure the stable and normal data transmission of the bus-box.
Renovation technical requirements:
1) Remove the existing monitoring module and communication equipment of the bus-box and replace it with a split measuring module and communication power all-in-one machine to restore the stability and normal data communication of the bus-box.
2) The upgrading and transformation of the bus-box will not change the communication mode of the existing communication management machine and the communication wiring structure of RS485 network.
3) The transformation of the bus box requires the communication data to complete the configuration software setting of the communication management system of the matched subarray.
4) All data of the bus box shall be sent to the monitoring system and the data shall be normal and accurate.
5) The split measuring module and the integrated machine shall be installed reasonably according to the distribution of primary components of the bus box to ensure a safe distance from the primary components.
6) Do not change the position of the primary components such as the positive and negative bus bars of the bus box.
7) The internal wiring specifications of the revamped bus box are neat and in line with the electrical wiring process standards.
8) After the communication repair of the bus box is completed, the monitoring data of the bus box shall be checked one by one with the actual operation parameters of the field equipment, and the telemetry status shall be correct.
9) Fire blocking and sealing of the reformed bus box shall be restored to the state before the transformation.
10) Shall not damage the container of the bus box, and ensure that the site is clean after finishing the work.
11) Transformation of bus-box The transformation scheme shall be prepared according to the internal layout of different types of bus-box in Table 5.2.1, and the most economical and suitable number of measured branches of the module shall be determined according to the number of different branches of the bus-box (branches of each measuring module shall be no more than 4).
12) Purchase a monitoring host, and coordinate with existing background manufacturers to install, deploy software, configure communication protocols and point tables, and realize the monitoring function of power station array area.
5.1.1 Requirements for split Measurement Modules
1) The number of branches measured by the split measuring module shall be no more than 4. Supports interchangeable installation in any order.
2) Split current measurement module current sampling independently, can collect positive and negative current, measurement range -25A to +25A, measurement accuracy requirements are not more than 1%.
3) The perforated Hall measurement with electrical isolation should be adopted, and the connection of split current measurement module should be connected by digital signal transmission.
4) The shell material of the product is flame retardant and safe and reliable.
5.1.2 Requirements for the Communication Power Supply Appliance
1) The all-in-one communication power supply machine has the function of self-collecting power from the bus box, and has the function of protecting input over current voltage and output short circuit.
2) Communication power supply integrated machine with bus voltage measurement function, measurement range DC200-1000V, measurement accuracy is not more than 0.5%.
3) The communication power all-in-one machine should have digital display, button function, status indicator, local button display to view branch current, bus voltage and other data.
4) Integrated package, PCB board and power supply shall not be exposed. Bidding Document 42
5) With lightning protection function.
6) Operating temperature: -20℃ -60℃.
7) It should have isolated RS485 interface and support Modbus-RTU protocol.
8) The communication transmission shall operate reliably and stably for a long time, and the transmission rate shall meet the communication requirements without data interruption, false death, abnormality and other phenomena.
The new DC bus box has the following features:
1. High reliability
Choose photovoltaic special lightning surge protector, can protect photovoltaic equipment from lightning damage, the auxiliary power supply is powered by PV series, as long as any PV series works properly, you can make the auxiliary power supply work properly, to ensure the normal operation of the monitoring module.
2. Bus box function
Measure the series current
Measure the voltage after the confluence. The voltage accuracy is 0.5%. Measure the working temperature in the box
The current acquisition mode is induction type, and the potting glue process has the characteristics of high precision, anti-interference and durability compared with the shunt scheme.
Group abnormal alarm (overvoltage, undervoltage, overcurrent, undercurrent, reverse current) alarm threshold can be set by oneself
Failure alarm of surge protector
The LCD bar chart displays parameters. O&m personnel can use the LCD to quickly locate component faults
The module adopts the potting glue technology, which can effectively resist interference in high altitude areas with low air density and high interference.
3. Flexible configuration
Enter the number of strings 4 to 24 optional and extensible
Photo of on-site bus box