Sixth generation of ripple control system receivers
The strides made in electrical engineering and electronics have resulted in technology migration which is used for commercial purposes. Such rapid progress has happened several times in the long history of ripple control systems. Today we see another step forward in the technology of ripple control receivers – the manufacture of a virtual receiver that has almost no physical parts, but is implemented as part of the firmware of the processing unit of the electronic meter and its software. These receivers will considerably influence the shape of meters in Europe, as well as the implementation of automatic meter reading (AMR) systems.
On 31 December 1899 Cesar Rene Loubery patented his system of remote control, which allowed the use of existing electricity lines to transmit commands in one direction, while at the same time continuing to deliver electricity. Today we use the following names for such mass transmission of commands: Rundsteuerung, Ripple Control (RC), Ripple Control System (RCS) or Ripple Control Command. The century-old use of ripple control systems has been accompanied by the occasional migration of technology, but the basic idea of the cheap and efficient mass transmission of information in one direction has remained unchanged – in the same way as the idea of radio and television, which date from the same period, are still used today.
The migration of ripple control system technology can be viewed in a number of ways and over a different time period. Nevertheless this migration in its previous five generation steps seems perfectly understandable to the majority of those familiar with the field. Similar five generation moves also happened in the domain of RC controlling switchboards, RC transmission and RC receivers. RC receivers make up the most significant part of an RC system in terms of both numbers and total cost, as they represent the majority of the price of an average and optimised RC system.
FIRST FIVE GENERATIONS
The first generation of receivers was electromechanical. The decoder was implemented with the aid of a synchronous small motor and a timer, camshaft and principle of convolution. The input filter was an electromechanical LC type with an output Reed-relay.
The second generation of receivers is recognisable for their LC input filter and electronic decoder. The filter is appropriate for reception of only one frequency. The electronic decoder enables the use of a considerably larger number of address commands. Transistors and integrated circuits (ICs) with a small level of integration were used for its production. This generation belongs to the concept of a typically centralised RC system, where the work of the receiver depends on the proper functioning of the switchboard and the transmitter. The predominant manufacturers of the second generation of RC receivers are Landis+Gyr, Zellweger, and Uher.
The third generation of receivers is electronic only. The filter of the receiver is implemented by an active filter, which can easily adapt to any frequency and is appropriate for mass production. The decoder is implemented as a purpose-built VLSI technology chip which considerably simplified mass production, increased reliability and lowered production costs.
This generation of receivers belongs to the concept of typically centralised RC systems, where the work of the receiver depends on the proper functioning of the switchboard and the transmitter. There is a noticeable trend of integrating the receiver into the housing of the electrical meter. The predominant manufacturers of the third generation of RC receivers are Landis+Gyr, BBC and Siemens.
The fourth generation of receivers is electronic only and is universal for all frequencies and all messages. The receiver filter is implemented by an active filter based on the SC principle – Switch Capacitor ICs. The decoder is implemented by a microprocessor, so that every receiver produced is the same and the device receives the final definition of frequency, selection of messages and functions via software. It is appropriate for mass production and integration into the housing of the electricity meter.
The message is typically 50 bit with address commands but without logical protection of the data. Such receivers have a number of autonomous functions which make them decentralised and less dependent on the switchboard and transmitter. The predominant manufacturers of fourth generation RC receivers are ABB, Enermet, Landis+Gyr and Siemens.
The fifth generation of receivers dates from 1994-1995, and is recognisable for its digital filter and its remote parameter setting. The receiver is implemented with a very small number of components, a high level of integration, and very high levels of reliability, which technologically favours mass production and easier integration into the housing of the electricity meter.
All parameters and functions of the receiver are determined using software with the aid of a PC interface, sent remotely over energy voltage lines with the aid of an RC message, which is now a protocol with more than 50 bits defined by the DIN 43861-3 standard. This communication protocol contains a protective cyclical redundancy code (CRC). The functions of the switchboard are distributed, partly into the transmitters and partly into the receivers, so that in the event of a break in the telecommunication connection of the transmitter with the switchboard or the transmitter with the receiver they continue performing all their functions.
The redundancy of RC system functions in this way is the most significant characteristic of a fifth generation RC system. With the redundancy of functions on the level of the software of the same single components of a fifth generation system (switchboard, communications, transmitter, receiver) the same or better reliability has been achieved compared to the concept of hardware duplication of critical elements of a system implemented with hot reserves, as is the case with the older generation equipment.
In addition to a series of standard user functions, the fifth generation receivers have a series of service functions which ease the maintenance of an RC system, such as memory of the last accepted message and all its received bits; memory of the level of the RC signal of the last received message; cumulative usage counters for each output relay; and counters of omitted transmissions, which changes the approach to maintenance of a modern RC system. This of course results in a lower total cost for a more reliable RC system, and a lower price per user of the electrical power supply network. With the new DIN43861-T3 standard, a protocol for remote parameter setting of a fifth generation receiver has been defined in such way that with a 50-bit message, it allows the receivers of older generations to continue uninterrupted operation in existing electrical power supply networks. This generation of receivers does not need maintenance and servicing. The predominant manufacturers of fifth-generation receivers are Elster-ABB, Landis+Gyr and Enermet.
SIXTH GENERATION OF RECEIVERS
The sixth generation of receivers are virtual receivers integrated into the electricity meter at a software level as part of the firmware. This generation also needs no maintenance and servicing. All the characteristics of the fifth generation of receivers were carried over into the new sixth generation. The paramaters can be set locally over the meter interface, either remotely via an RC message or – for meters that have a modem and an appropriate communication channel – remotely via the AMR system.
The virtual receiver has almost no special hardware parts, because it uses the existing capacities of the meter’s microprocessor. A receiver implemented in this way completely supports the IEC 611037, IEC 611038 and DIN 43861-3 (01 or 02) standards. The electricity meter synergistically unifies time switch, ripple control receiver and automatic meter reading functions and technologies in such away that they enhance each other.
The virtual RC receiver can be integrated into other energy devices and electrical appliances that have an appropriate microprocessor, and whose use is in some way dependent on electricity tariffs or precise time.
Meters with an integrated RC receiver can control tariffs, memorise and reset monthly meter readings of energy and power, control thermal consumption and initiate remote disconnect.
With such sixth generation RC receivers, the continued use of RC technology for the management of tariffs and time synchronisation in electricity power supply networks is guaranteed, with very low costs per network user and very high levels of reliability. An electricity meter with an integrated virtual RC receiver has already been developed by RIZ Zagreb, with an active energy in the order of a kWh, reactive energy in the order of a kVArh, power in the order of a kW, integrated time switch and integrated RC receiver and power limiter, as well as a local AMR interface and remote control AMR.