中、低压电气智能终端设备在火力发电厂的应用

针对应用于火力发电厂厂用电系统的中(6/10kV)、低(380V)压系统的控制特点,提出了总线智能终端设备应具有保护、遥控、遥信、通信等基本功能。中压系统智能化设备一般配置数字式保护测控装置及数字式测控装置。低压系统智能化设备一般配置智能电动机控制器、智能仪表、综合保护测控装置或框架断路器智能控制单元等。目前,电厂智能终端设备常用的现场总线类型主要有:基于Modbus-RTU协议的RS-485总线、CAN总线、Profibus-DP、Lonworks等4类,此外,工业以太网的应用日趋广泛。对于控制对象较少的电厂,采用RS-485总线、CAN总线较为经济适用,而对控制对象众多的大、中型电厂,则建议采用Profibus-DP、Lonworks、以太网等通信速率高、节点容量大、传输距离长的总线。

Application of MV and LV intelligent electrical terminal device in fossil fuel power plants

According to control features of MV(Middle-Voltage)(6 kV or 10 kV) and LV(Low-Voltage)(380 V) system in fossil fuel power plants,basic functions of the intelligent field-bus terminal device are put forward,such as protection,remote control,remote signaling and communication.The MV system is normally configured with digital protective and I/O device,or intelligent I/O device.The LV system is normally configured with intelligent motor controller,intelligent instrument,integrated protective and I/O device or control unit built in CB.There are four common field-bus types for intelligent terminal devices in power plants:Modbus-RTU protocol-based RS-485 field-bus,CAN bus,Profibus-DP and Lonworks.Now,application of industrial Ethernet is becoming more widely.For power plants with limited control objects,RS-485 field-bus or CAN bus is more applicable and economic.For medium and big power plants,it is suggested to apply those buses with high communication speed,large node volume and long transmission distance,such as Profibus-DP,Lonworks and Ethernet.