The smart grid is an advanced electricity supply network. By using information and communication technologies, this system detects and collects the status of power supply at the supply end and the consumption status at the consumption end through digital or analog signals. These signals will in turn be used for the adjustment of power generation and distribution, or the adjustment of power consumption capacity for households and businesses. In so doing, this system allows for energy efficiency, reduction of dissipation, and reinforcement of the reliability of the power grid. For the proper control of the information on power supply and power consumption of the grid, the smart terminal (FTU/DTU) for the distribution of power supply of the grid will be necessary for such purpose.
The critical role of FTU/DTU in power grids
The terminologies and products commonly seen in smart grid are FTU (feeder terminal unit) and DTU (distribution terminal unit). FTU is the terminal monitoring the switching of the feed line and is a switch-monitoring device installed at the 10KV circuit breaker and fuse switch. The main function of this device is to collect the electric parameters of the line connecting to the switches and pass the information on these lines to the system at a higher level. DTU is the terminal installed at regular power switching stations (substations), small outdoor switching depots, ring main unit, small power transforming stations, and box-type substations for data collection and monitoring. The primary function of this device is the completion of the location signals of the switching equipment at the stations, execution of the remote command from the main station, and the activation and deactivation of the distribution and combination brakes.
Automated power grid covers various areas of applications and there are far too many products and suppliers available in the market. Shanghai Huanhe Electronics Technology Co., Ltd. is a technology firm specialized in the technology research and development and application technology services in power supply and related domains. It has launched automated FTU/DTU products in the market of China. These products are the result of joint venture between Huanhe Electronics Technology and Arrow ESC. Indeed, Huanhe Electronics Technology is a joint venture partner of the ACES (Arrow Consultant Engineering Service) project. This product series is highly expandable and compatible, and can support GPRS/CDMA, dual-ring fibre optic Ethernet, WIFI, and Bluetooth in remote communication for on-site tracking and display of the web. The wireless Zigbee and 485 communications at lower level, and the main connector and specification of power supply are covered. In addition, modularized design is applied to the connector for reliability, flexibility, and low cost. On this basis, it can support the latest DL/T721-2013 and IEC61850 standards readily.
The automated FTU/DTU launched by Huanhe Electronics Technology shares the same hardware board with the monitoring device and can be expanded to different boards depending on the size of the site for flexible allocation and optimization of the price-performance ratio. A CPU board is built into the FTU/DTU baseboard with the use of ADI AD7606 and ADUM1201 chips with default supply of two 10/100M Ethernet RJ45 ports, two RS485 ports, a RJ45 maintenance port, and a GPS synchronous clock interface (supporting IRIG-B or 1PPS). There are 6 LED indicator lights mounted on the board. When there is no human-machine interface, the device can show the status of work or failure. The I/O board can support 13 input lines and 2 4-unit output lines, and is typically applicable to the collection and control of 2 lines. The AI board supports up to 12 AC analog input lines, the voltage and current can be flexibly allocated by soldering and software. The PWR board supports power input with the performance of battery charging and release functions, and connects to two 24V auxiliary power output lines. At the same time, it can also support the measurement of 3 DC lines.
The automated FTU/DTU software platform of Huanhe Electronics Technology is embedded with the RTOS (real-time operating system), which is designed in module with flexible allocation for supporting the 2nd development of the users. The high-precision collection is one level higher than its industry peers and can achieve 0.2% accuracy for voltage and current in the range of-40~85℃, and 0.5% accuracy for active power and reactive power with high accuracy at low end. The cost of the hardware structure is the lowest in the industry.
In the wake of global development of energy saving and carbon reduction, the saving of unnecessary energy consumption in the power grid will be the objective for the private and public sectors alike. With the installation of smart grids and related equipment, the efficient use of energy can be substantially achieved. The potential of smart grids and related equipment in the market will be promising and deserve the consideration of firms to engage in the development of related products.