COVER STORY Micro-Power RF Ad-Hoc Networking for AMI System by one DCU, with up to 12 months’ data saving. The downlink communication between the DCU and the energy meter can be effected by means of RF, Zigbee, or PLC, among others, depending on how the data collector works. Meanwhile, the HES uplink communication can be effected via GPRS, CDMA, WCDMA or Ethernet. The DCGL23 series RF data collector (with Zigbee energy included) (b) is used to read a group of meters with RS485 ports, and can be converted into a parent MESH node to form an ad-hoc networking system. Similarly, the DCGL13 series PLC data collector (c) can be used to read a group of meters with RS485 and RS232 ports, and can be converted into a parent PLC (S-FSK/PRIME/PLC-G3, etc) node with router function, forming a PLC networking system based on the IEC61334 protocol. STAR-NET has been able to support the various micro-power RF networking communication in sub-GHz (408MHz/433 MHz/470M-510MHz/780MHz /868MHz/ 915MHz) and Zigbee 2.4GHz, which supports low-voltage PLC (DSSS/S-FSK/ PRIME/PLC-G3) communication. In special circumstances, hybrid networking can also be enabled. Smart Meter Layer There are three categories for this layer, depending on operational scale. Large power users: The auxiliary power supply prioritised HV/LV three-phase DTS27 series meter (CT connected) with 0.5S/0.2S accuracy class is mainly used for large power users, covering all the above 415kVA sub-station capacities. The smart meter is used to measure bi- directional active energy, four quadrant reactive energy, real time current/ voltage, frequency, active/reactive METERING INTERNATIONAL ISSUE – 1 | 2015 power, TOU billing, event logging, load profile recording, as well as harmonic distortion and flicker recording. a DJGZ23 DCU The energy meter series is designed to support interchangeable communication modules, with various communication means, such as GPRS/WCDMA, PLC, RF, Optical Fibre etc. Due to the scattered geographic nature of the large users, meters with GPRS modules are preferable. The whole series supports the IEC62056 DLMS/ COSEM Modbus protocol. Light industrial and commercial users: We recommend our DTS27 series of LV direct-connected smart three-phase energy meters (accuracy class 1.0) and DTSY23S series STS keypad prepayment meters. DIN/BS/ANSI wire connection methods are supported. DCGL23 RF Data Collector For this meter series, users can opt for either credit or prepayment type, both of which support communication protocols for IEC62056 DLMS/COSEM, ANSI C12.18/19 etc. b Residential Users. Our DDS26D, DDS26E, DTSY23S and DDSY23S energy meter series are designed predominantly for residential use. DIN/BS/ANSI wire connections are supported, and anti- tampering features such as anti-magnet, reversal current and bypass detection etc. are reinforced. RF/Zigbee, S-FSK/PRIME/PLC-G3, GPRS/ CDMA/WCDMA communication modules are ready to be integrated on these meters for the purpose of remote reading, supported by IEC62056-21, DLMS/COSEM, and ANSI C12.18/19 communication protocols. An optional 100A internal relay can be fitted, enabling the meter to be switched between credit and prepayment mode. c DCGL13 PLC Data Collector Diagram 2. DCU and Data Collector 9