Abstract: This paper introduces the application of ABB ACS-510 frequency converter in thermal network and provides a method to control frequency converter using Modbus. Keywords: inverter square load 1 Introduction Heat network heating with good heating effect, pollution-free characteristics, the thermal station as a major part of the heating network, the thermal station level directly affects the user's control of the use of warm conditions, thermal station energy saving is also hot Energy-saving main part of the network, so energy saving station, safe operation, of great significance. 2 Project Overview Harbin Airport Development Zone, central heating project a total of 120 thermal stations, heating area of ​​about 5.7 million mm2, the total load of 10000J / H, a network of water temperature design 130 ℃ ~ 70 ℃, hot water heating Heating, heating station functions mainly for residents and factories heating, heat station for the first network and the second network for heat and the second pressure, the second pressure and the circulation pump inverter control, the project thermal station using ABB ACS510 series inverter as a circulating pump and make-up pump drive part of the heat level to improve the level of automation, to achieve energy conservation. 3 Process Profile The composition of the thermal station [1]: mainly by the heat exchanger, self-control screen, circulating pump, make-up pump, communication line, as shown in the figure. The figure is composed of a Schneider PLC, which collects various parameters and status of the site into the PLC, and the PLC will send the collected data to the dispatch center through the ADSL mode . Dispatching Center will return the user room temperature signal from the dispatch center back to the thermal station PLC. Realize the automatic operation of the thermal station according to the method of controlling the secondary water supply temperature and the water supply flow according to the indoor temperature of the end user. Whether the user's indoor temperature is up to the standard based on the temperature curve and the outdoor temperature released by the city heating office. 4 heat station function Once the net heat exchange through the heat exchanger, the second network of hot water to all users, the operation of the thermal station is superior and poor mainly to the station end-user indoor temperature reaches the city's The heating standard and the operation cost of the thermal station and the energy conservation standard are the standards. Based on the above, the heating method of the thermal power station adopts the combination of quality and quantity adjustment to achieve the heating standard and the energy conservation. Quality (1) is through the regulation of a network of water flow control valve to control the secondary network of water temperature. Quality control is simple, but less energy-efficient. The amount of adjustment (1) is in the circulating pump plus variable frequency control (3), by adjusting the secondary water flow to ensure end-user room temperature compliance, this way the energy saving effect is very good. We control the way is based on the amount of quality-based optimization of the control mode, this control mode can save 30% of electricity per year, through the circulating pump frequency and make up the pump frequency to improve the imbalance (3) can save 20% 30%. To ensure that the heat network end-user room temperature standards and the maximum degree of energy conservation, the economic benefits are impressive. It is a square load application, ACS-510 lower cost and has its own MODBUS communication function, we use the MODBUS bus to control the inverter, including the frequency of the start, Stop, speed AI given, etc., the inverter operating parameters passed through the MODBUS bus to the PLC, PLC back to the dispatch center, this way the control cabinet assembly convenience, because less wiring, low failure rate of auxiliary components, this Through the bus control speed to AIsubstation of district heat supply network given, its high precision, effective. Station set up two 37kW circulating pump, two pumps one main and one standby. Inverter with a delay of two. (1) Inverter debugging J2 is set to "off". Circulating pump drive not set to last address. 9902 set to "5" via control panel 9902 set to "5" "HAND / AUTO" set to 9903 to 380 9906 set to "1" 9907 set to "50" 9908 set to "2900" 9909 set to "37" Set communication function 53 Group number setting 5302 Set to "2" 5303 Set to 9.6kbits / s 5304 Set to "1" 53 Group parameter setting should be the same as that in the PLC communication protocol Set to "8", " 1 "" R ", the address is set to" 1 ". 98 Group parameter setting JZ set to "off" 9802 Set to "1" Start standard mod Corresponding method of inverter and PLC communication register Address of inverter register Corresponding setting of PLC address 1102 External control 1 / External control 2 Select 4001 8 1103 External Control 1 Reference AI 4002 -32676 ~ 32676 Reference 1108 Settings 0102 Speed ​​40102 0103 Output Frequency 40103 0104 Current 40104 0301 Bus Status Word Bit 0 40301 Bit 0 How to start the inverter The PLC sends data to the inverter 4001 Move Move to 4001; Move to 4001; Move 101 to 4001; Move 101 to 4001; At this moment, the frequency converter starts, sends the rotational speed signal to the frequency changer AI 4001 through the main line. The speed signal of the inverter is controlled by the PLC according to the secondary network supply and return pressure difference of the thermal power station, that is, the secondary water supply flow rate signal, controlling the supply and return pressure difference to realize the real-time flow control. 6 Replenishment pump control Replenishment frequency The frequency converter with ABB ACS-510 3kW fan pump load is very similar to the recycle pump, but its address is set as "3" and the inverter J2 is set as "on" ", Refilling the inverter is the last piece of equipment Modbus. Replenishment speed control signal from the inverter to the drive by the PLC "4003" to ensure that the secondary network of constant pressure hot water. 7 Conclusion Through the heat station circulating pump plus inverter to achieve the amount of heating network shows that ACS-510 inverter energy saving (3) the effect is very obvious, the use of ACS-510 inverter to control the water heating inverter to reduce the offset network to save water. Using ACS-510's own modbus bus to control the operation of the inverter saves the investment of equipment in the thermal power station. Bus control reduces many external components, reduces the system failure rate and increases the reliability of the system. The operation of the ACS-510 inverter in the thermal station proves that the energy-saving effect of the inverter used in the circulating pump and the makeup pump of the heat network is very good, which is a very worthwhile promotion of the inverter application.
