Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R21/00—Arrangements for measuring electric power or power factor
  • G01R21/133—Arrangements for measuring electric power or power factor by using digital technique
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
  • H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
  • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
  • H02J13/00007—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using the power network as support for the transmission
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
  • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
  • H02J13/00016—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus
  • H02J13/00017—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus using optical fiber
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
  • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
  • H02J13/00034—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving an electric power substation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02B90/20—Smart grids as enabling technology in buildings sector
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
  • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
  • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
  • Y04S10/30—State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
  • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
  • Y04S40/00—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them
  • Y04S40/12—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment
  • Y04S40/121—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment using the power network as support for the transmission
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
  • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
  • Y04S40/00—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them
  • Y04S40/12—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment
  • Y04S40/124—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment using wired telecommunication networks or data transmission busses

Definitions

• the present invention refers to a system for the remote control of the electricity distribution network and the telereading of the electricity, gas, water and other services meters of the customers connected to the same network. More specifically the present invention refers to a system which uses centralized and distributed intelligence to manage the information and carrier currents at relatively high frequencies over the wires of the electricity networks to transmit the information.
• the carrier currents system is implemented according to an original method, which, unlike the traditional one, does not utilize high frequency traps and by passes, at the network nodes. This method allows the use of the power distribution network without the expensive changes required by the traditional solution.
• Voltage (LV) radial networks as they are configurated for the distribution of the electricity and by properly addressing the various substations and the customer meters.
• the method of properly addressing and routing the messages to their final destinations requires that the state of the network is very frequently updated.
• This function is performed by the system subject of this invention and the updating of the state of the network, a very important information in itself, has to be seen as an added value for the system.
• the system mentioned above can provide, one by one or in an integrated way, the following functions:
• Figure 1 shows the architecture of the system according to the present invention
• figure 2 is a table giving the meaning of the symbols used in figure 1 and in the subsequent figures
• figure 3 shows a diagram for routing the messages
• figure 4 shows a diagram of the high frequency coupling device for the injection/pickup of carrier- current signals on the MV network
• figure 5 shows a the architecture of the ACP apparatus
• figure 6 shows the architecture of the ACS apparatus
• figure 7 shows the architecture of the Remote Terminal Unit (UPT)
• figure 8 shows the architecture of the Peripheral Electronic Unit (UEP) which is installed inside the metering apparatus for domestic LV users
• figure 9 shows the Multifunction Portable Terminal
• TEM Multifunction Portable Terminal
• figure 11 shows a LV network diagram as it appears on screen in an STM graphic workstation
• figure 12 shows the structure of the message on the MV network according to the used protocol
• figure 13 shows an example of the "store and forward" procedure on a LV line
• figure 14 shows a map of the remote controlled HV/MV substations within a certain distribution zone
• figure 15 shows the topological diagram of a MV distribution network
• figure 16 shows the diagram of a MV feeder
• figure 17 shows the sub-diagram of a MV feeder section
• figure 18 shows a typical HV/MV Substation
• figure 19 shows a diagram of a secondary substation with one bus-bar
• figure 20 shows a diagram of a secondary substation with three bus-bars
• figures 21 and 21bis show an example of the automatic sectionalizing' procedure on an overhead MV feeder
• figure 22 shows an example of the automatic sectionalizing procedure on a MV underground feeder
• figure 23 shows a diagram of the pulse generator device installed inside the metering apparatus
• figure 24 shows the metering apparatus and the electronic units required by the system for the various categories of users defined as a function of their subscribed power demand
• figure 25 and figure 26 show two types of electric metering apparatus
• figures 27a and 27b show the insertion of the electronic unit into the metering apparatus in the case of an individual installation and in the case of the installation over a centralized board
• figure 28 shows the structure of centralized board for residential low voltage customers
• figures 29, 30, 31 show different types of metering apparatus
• figure 32 shows the connection of a metering apparatus through current transformers for an LV customer
• figure 33 shows an
• System architecture as shown in fig. 1 is divided into the following subsystems: STU-x for management of the HV (high voltage) network and the Primary Substations in a certain territorial unit (District) .
• STM for management of: MV (Medium Voltage) network, secondary substations and users in each territorial sub-unit (Zone) into which the territory controlled by STU-x is divided;
• MV Medium Voltage
• Zone territorial sub-unit
• STU-x is at the highest level in the hierarchy and is capable of managing up to 200 Primary Substations
• HV/MV transformation substations therefore it can supervise and control an HV network of notable proportions.
• It can interface on the one hand with other STU-x systems and/or with remote Host Computers, by means of packet switching geographical networks, and on the other hand with one or more STM systems from the component territorial sub-units, by dedicated Point-to- point channels.
• STM Peripheral Work Station
• SOP Peripheral Work Station
• Both the STU-x and STM subsystems are organized on Ethernet type Local Area Networks; the vital components of each system, including the computer, are doubled, and there are special procedures to switch from the faulty component to the healthy one.
• the FRONT-END Computers use the same Hardware base, but can adopt different types of protocol and manage communication with the field autonomously.
• the territorial sub-unit (Zone) is provided with STM
• the information relating to the Zonal Primary Substations is acquired directly by the FECs of STU-x (Fig.l) .
• the information from the Secondary Substations is acquired by the FECs of STM.
• This information comes from the Primary Substation Apparatus (ACP) , and can be divided into two main categories: a) Information relating to the subsystem for the automation of the MV network, coming from the Remote Terminal Units (UPT) in the secondary substations; b) Information relating to the subsystem for Customer Service Automation, coming directly from the metering devices for MV users, or from the Secondary Substation apparatus (ACS) for LV users.
• ACP Primary Substation Apparatus
• UPT Remote Terminal Units
• ACS Secondary Substation apparatus
• the work stations (Fig. 1) installed at District (SOD) and Zone (SOP) level are practically identical to each other, and are high definition graphic stations.
• the telecommunications sub-svstem Communication between the Primary Substations and the Control Center is carried out through standard vectors, and so it is possible to use radio links, dedicated telephone lines, carrier-current signalling on HV lines, etc.; in this way, each Zone, is connected to its own primary substation.
• each Primary Substation to its own secondary substations and connection between the LV meters and the secondary substation by which they are fed, is carried out by a line carrier transmission system, on the same MV and LV distribution networks.
• the non-existence of High Frequency by-pass on the switching elements means that the interruption of a feeder caused by a fault produces a break in the communication link at that point in the system.
• the solution to this problem consists in providing the Remote Terminal Units (UPT) with a certain amount of autonomy, .so that they implementing on them a logic that allows automatic re-closure of the switches in the substations to be reenergized, as soon as the faulty section has been isolated.
• UPT Remote Terminal Units
• any variation in network connection produces a change in the configuration of the Telecommunications System which, in order to route messages, has to refer to a real time updated Data Base, containing the status of electrical connections in the network. It must be noted that the above does not form what could be defined a "negative characteristic". It is, in fact, a novel and innovative form of use of what was considered a negative aspect, that is to say a fault in carrier-current signalling systems when considered in general.
• one of the main aspects of the present invention makes advantageous use of what was up to now considered a limitation in line carrier transmission systems.
• the subsystem (STM) for distribution automation in one of the territorial sub-units mentioned above is managed by a control center (100) .
• This center by means of the FRONT-END computers (101) communicates using dedicated multi-point lines with the HV/MV substations in the territory covered.
• the message is delivered to the ACP apparatus (102) , from which the line carrier system, according to the present invention, departs.
• the ACP (102) has a series of independent output channels which, by suitable coupling devices (103) , allow injection/pick-up of the carrier-current signal on each medium voltage bus-bar (104) in the substation.
• Substation MV bus-bar with the interposition of MV circuit-breaker (105) , and each of these lines feeds a series of MV/LV substations (106) connected in cascade. Once one of these substations has been reached, the signal is picked up by a coupler (107) and sent to the ACS apparatus (108) or sent directly to a medium voltage customer metering apparatus (109) if the substation supplies a user of this kind.
• the ACS (108) connects with the low voltage (LV) supply bus-bar by a capacitative coupler that allows the messages to reach the low voltage meters (111) installed in the user premises.
• the ACS is connected to the UPT apparatus (110) , which allows remote signals to be sent and remote commands destined for the switches in that secondary substation, to be performed.
• the type of modulation used is narrow-band (FSK) , and the transmission frequencies are the following: approx. 72 kHz for the MV network approx. 82 kHz for the LV network both within the range of 9-95 kHz, assigned by CENELEC to electric utilities.
• FSK narrow-band
• the modem used which is of the single-chip type, is the same for both the MV and the LV network.
• phase- phase mode is used in the MV network
• phase- neutral mode is used in the LV network. The following are therefore used:
• the solution chosen for the MV network does not influence operation of the directional earth protections in the HV/MV substations, and minimizes crosstalk at open switches.
• the MV coupling device is confined inside a small metal oil filled box, and is connected to the line by means of air or gas insulated bushings, for installation on an air or gas insulated cell, respectively.
• Transmission power is rather low (-1W) both on the MV and on the LV network.
• the used procedures are tolerant with delays of several hours in the transmission of signals; this, for customer service automation, makes it possible to avoid transmission during the least favourable hours of the day (hours of maximum load) .
• the transmission rates are the following: 1200 it/sec. on the MV network 600 bit/sec. on the LV network.
• the system in addition to the processing resources at the control center, the system, according to the present invention, also uses the peripheral apparatus described below.
• ACP ACP
• the ACP, or Primary Substation Apparatus (figure 5) , situated in each HV/MV substation, is the communication interface between the FEC installed in the control center and the peripheral apparatus connected to the Medium Voltage network (ACS, UEPM, UPT) .
• the hardware architecture of the apparatus is modular and uses a System bus to interconnect cards, thus allowing sizing that is aimed at the specific needs of each site.
• ACP The fundamental blocks of ACP are: a) Processing unit (CPU, memory and accessory circuits) : b) Connection to the Portable terminal; c) MV network RX/TX modules; e) Synchronization unit with MV zero crossing.
• the ACP can connect with:
• - ACS apparatus by means of a certain number of channels, each one of which is coupled to a Primary Substation MV bus-bar by means of capacitive coupler.
• Each channel is bi-directional half-duplex and can manage the traffic in parallel with the others on the various substation bus-bars.
• the protocol is specialized multipoint HDLC-MT type, with the ACP acting as Master. All the messages sent on the MV bus ⁇ bars are synchronized with the zero crossing of the alternate current at 50 Hz, that is to say there is a positive zero-crossing indicator supplying the start of the message.
• the ACP node is only assigned tasks connected with communication, and in particular the following functions:
• 6) installed in the MV/LV substations, is a slave node of the communications network on the medium voltage lines and the Master node for the Low Voltage communications network.
• the Hardware is characterized by a high level of integration with sharing of functions between the various units, which takes into consideration not only functional aspects but also industrialization aspects.
• the functional blocks making up the ACS are the following (fig. 6) : a) CPU and Power-fail management circuits; b) Static RAM memory; c) FLASH_EPROM memory for the application programs code; d) EPROM memory for Bootstrap programs and those for management of portable terminal loading; e) EEPROM memory for semi-permanent ACS data (address, routing tables, etc.) ; f) A/D converter for measurement of network voltage; g) Real Time Clock for management of time/date with Back-up capacitor to guarantee operation of the clock for 48 hours in the absence of power supply; h) MV Multiplex to share the MV transceiver with the UPT; i) LV Multiplex to share the single serial channel with the three LV transceivers, each one connected to one phase and neutral; j) MV transceiver; k) LV transceiver; 1) LV couplers; m) Dual-input power supply (220 V AC - T phase, 24V DC)
• the ACP by means of the MV network, to which both are connected by a capacitative coupler; communication can be direct or through a number of ACS repeater units.
• the Electronic units in the LV metering groups (UE-BT) through the LV network - the LV transceivers, one for each phase, can only be used separately according to the phase involved;
• the Portable Terminal by means of an asynchronous serial interface with optical coupling of the same kind as that used by the ACP.
• the UPT or Remote Terminal Unit by a standard RS232 interface; this connection has the sole aim of allowing the UPT to use the MV transceiver for communication with the ACP.
• the ACS node is assigned tasks connected with communication, and in particular the following functions:
• UPT The UPT or Remote Terminal Unit (fig. 7) is only present in remote controlled secondary substations, where, in addition to its normal functions of actuating commands and transmitting remote signals, it is also used to apply a series of automatic rules that allow a faulty section of MV line to be identified and sectionalized.
• the Hardware is characterized by a high level of integration, the functions being shared between the various units like for the ACS apparatus.
• the architecture can be divided into two main sections, each one managed by a separate bus: the processing section and the section for interface with the field.
• the functional blocks forming the UPT are the following (fig. 8) : a) CPU and support circuits; b) Static RAM memory; c) FLASH_EPROM memory for the application programs; d) EPROM memory for Bootstrap programs and those for management of portable terminal loading; e) EEPROM memory for semi-permanent ACS data (address, routing tables, etc.); f) Real Time Clock for management of timing; g) System Watch Dog (WD) ; h) Controller for 2 serial channels (connection with ACS and with the portable terminal) ; i) RS232 interface for connection with ACS; j) RS232 interface and opto-electrical converter for connection with the Portable Terminal; k) Connection interface between the bus of the processing unit and the bus for dialogue with the field;
• the UPT can connect with: - The ACP by means of the MV network to which both are connected by a capacitative coupler; communication can be direct or through a number of ACS repeater units.
• the ACS by means of a standard RS232 interface; this connection has the sole aim of allowing the UPT to use the MV transceiver for communication with the ACP.
• Another UPT by means of the MV network during identification of the faulty section of underground lines (with RG) .
• the Portable Terminal by means of an asynchronous serial interface with optical coupling like that used by the ACP and by the ACS.
• the main functions carried out by the UPT are the following:
• Remote control of the installation actuation of commands on switches, production of status information, pre-processing and transmission of elementary signals from the field, etc.
• - Identification of Faulty Section group of rules and procedures which are applied automatically by the apparatus to allow identification of the faulty sections of MV line
• dialogue with the center by means of the ACS in HDLC-MT protocol;
• the UEP or Peripheral Electronic Unit associated to the meter for each MV and/or LV user performs a series of communication and data processing functions.
• the functions and different types of electronic unit will be illustrated in the following; the block diagram of a UEP for single-phase LV user is given as an illustration (fig. 8) .
• the Hardware architecture shows the following basic blocks: a) Processing Unit (CPU, memory and accessory circuits) ; b) Opto-electronic transducer connected to the impulse emitting device housed inside the new power meters; c) Tripping device for the thermo-magnetic switch; d) Transceiver coupled to the LV line upstream of the meter; e) Liquid Crystal display for user; f) Power supply connected to the LV line upstream of the meter.
• CPU Processing Unit
• memory and accessory circuits Opto-electronic transducer connected to the impulse emitting device housed inside the new power meters
• c) Tripping device for the thermo-magnetic switch d
• Transceiver coupled to the LV line upstream of the meter
• e) Liquid Crystal display for user f) Power supply connected to the LV line upstream of the meter.
• the UEP can connect with the following:
• the ACS by means of the LV network and HDLC- BT protocol; - Another UEP, again by means of the LV network and HDLC-BT protocol;
• a Portable Terminal by means of the LV network and HDLC-BT protocol by means of the LV network and HDLC-BT protocol.
• the UEP performs the following functions: Basic timing management with clock/calendar functions;
• thermo-magnetic circuit-breaker Management of commands for tripping the thermo-magnetic circuit-breaker
• the communications function also comprises any dialogue with an optional electronic device that the user may install in his home, and which has the function of displaying information, sent directly by the Electrical Company, relating to energy consumption and, in the more sophisticated version, of performing load optimization activities.
• the System also provides a Multi-function Portable Terminal (TEM) , using which it is possible to connect to all the peripheral apparatus mentioned above.
• TEM Multi-function Portable Terminal
• the TEM (figures 9 and 10) is made up of a metal case containing on its inside:
• transceivers for the LV network - 1 asynchronous serial interface with optical coupler
• the personal computer is provided with suitable software packages for management of all types of protocol used by the System according to the present invention.
• Interactive procedures developed ad hoc allow the TEM to perform the following activities:
• Dialogue with ACP and with all the nodes in the network (both MV and LV) that are hierarchic dependent on it, in a manner similar to that used between the FECS apparatus and the Control Center;
• the dialogue is managed autonomously by the ACPs on the MV network and by the ACSs on the LV network, and takes place in parallel on each independent communication island. More specifically, it is possible to identify: - independent communication islands on the MV network, made up of all the lines connected to the same LV bus-bar in the Primary Substation. On each of these islands the ACP manages dialogue with the ACSs and with the UEPs of MV users in parallel; in particular the ACSs in each island are interrogated cyclically to check their connection status.
• the ACS interrogates the UEPs cyclically to check their connection status.
• the MV network is represented in a classical manner using nodes and branches, the LV network is represented in "Sections" (figure 11) ; as the section is a part of the LV network that cannot be further sub- divided by switches. Basically speaking, the section can be defined as a part of the LV network which is divided from the rest of the network by a certain number of switches, and which does not contain any other switch inside. As a number of LV metering devices are connected to each Section, the address for one of these is made up of two sub-fields: - the section number, called the "main address"
• This address is stored within the meter's electronic unit when it is activated.
• each section is fed at all times by a specific transformer, and therefore all the metering devices within the section are connected to the same transformer. Consequently, it is not necessary to interrogate all the electronic units to ensure that the section is actually connected, but it is sufficient to interrogate just one. If this responds, the section, and therefore all the meters in that section, are connected; if it does not respond, they are not connected. In this way, updating of the network connection status is very quick.
• b) By reserving, within the section, the number 1
• the ACS memory does not contain any information relating to the meters, but only a small amount of information relating to the LV network, which can be fed from the substation in which the ACS is installed, more specifically: - the list of sections that can be fed from that substation;
• Every message transmitted by the center must contain, as well as the address corresponding with its final destination, an indication of the route it has to follow.
• this route is unique and is defined by the HV/MV substation and by the MV/LV substation (in the case of LV users) feeding the user under consideration (or the substation under consideration, in the case of messages for remote control of the network) at the time of data transmission.
• Routing also includes the address of certain intermediate MV nodes and the masters of certain intermediate LV sections, to be used as transmission relays in the "Store and Forward" procedure.
• An example of relay procedure performed on a LV feeder is the following.
• the format of the LV message has the structure shown in figure 12; attention should be focussed bear on the following fields:
• IND address of the station to which the message is destined
• - CTL control
• RCP Message for repetition control
• REP (repeat) contains a variable number of addresses relating to the relay stations and the final destination;
• INF information field: contains the application message destined for the final destination.
• INF information field: contains the application message destined for the final destination.
• FIG 13 which shows the hypothetical dispatch of a message by the ACS to UE using two relay stations Rl and R2, let us analyze the sequence of outgoing and returning messages on the LV line.
• the ACS receives a request for communication with the UE node; from the routing table the relay procedure manager sees that direct communication is not possible, and that it is necessary to use relay stations Rl and R2. It therefore prepares a centrifugal message with a final address equal to the UE node, sends it to Rl and reverts to reception mode with the address Rl (the ACS has no address within the LV network for which it is MASTER) , setting a suitable Time-out.
• Rl receives the message and recognizes it as being destined for the UE via R2; at this point it re-formats the message, transmits it towards R2 and reverts to reception mode with the address R2, setting a shorter time-out to that set by the master node.
• R2 receives the message from Rl, recognizes the final destination, re-formats the message and sends it to the UE node. It then listens in with a suitable time-out (lower that set by the master) , with the address of UE.
• the UE recongizes the message as personal to itself and sends the response to the Master with its own address (UE) as destination.
• R2 which was awaiting a centripetal message with the address UE, receives the message, cancels the reception timer, re-transmits the message with its own address (R2) as destination, and then reverts to standby with its own normal network address (R2) .
• Rl which was awaiting a centripetal message with the address R2 , receives the message, cancels the reception timer, re-transmits the message with its own address (Rl) as destination, and then reverts to standby with its own normal network address (Rl) .
• each relay station is in reception mode with the address of the relay station downstream, thus knowing that it awaits a reply from a slave node and that once reply has been received it can relay it using its own station address; the messages travelling in a centripetal direction can have a normal message format with the REP field empty, resulting in an improvement of overall performance.
• the various time-outs in reception are calculated by the intermediate nodes according to the communications rules contained in the sub-field D of CTL. Any relay errors are managed by generation of an RCP message.
• This message generated by the relay station for which the reception time-out triggers, has the address of the generator node in the field REP and is transmitted in a centripetal direction in the same way described above.
• routing of the message is strictly dependent on an up-to-date knowledge of the connection status of the two MV and LV networks; this information is found in the STM sub- system and is obtained by the following main steps.
• Updating of the status of MV line switches by the activity carried out by the STM itself to manage the MV network, also bearing in mind the cyclic interrogation activity performed by the ACP in the Primary Substation on the MV nodes fed by the latter.
• Each ACS device performs a cyclic interrogation directed exclusively to the Masters of the sections fed by the MV/LV transformer within the same substation (section of the supplied LV network) , or connected to the preceding sections by a switch that is normally open (section outside the periphery of supplied network) .
• the "master” responds to the ACS, thus confirming that the section is still connected to that transformer.
• the ACS sends a new message to the "Master” of the section to start a data updating procedure towards electronic device within the user's home.
• This procedure assigns a clearly defined amount of time to each meter in the section to send certain data from its UEP to the respective electronic device that may be installed with the user.
• the ACS proceeds to interrogate the master of another section.
• A2 The "Master” does not respond, thus permitting the ACS to note that the section is no longer connected to that transformer.
• the ACS records this information and reverts to "Alarm State" to allow the ACP to record this information and pass it on to the STM in order to update the network connection status.
• the ACS proceeds to interrogate the "Master" of another section
• the ACS performs the same operations described in the point Al to allow transfer of information from each UEP to the respective user device and performs the operations described in point A2 to update the working configuration of the STM.
• the ACS performs the synchronization of the clocks in the meters within the section, which, for cost reasons, are not provided with a back-up power supply and which therefore loses synchronization when the LV section is transferred from the network supplied by one transformer to the network supplied by another one (this transfer operation, in order to avoid parallel working of the two transformers, requires the section to be deenergized for a short period) .
• the man-machine interaction procedures make use of entirely graphic environment procedures and real-time windows systems to guide the operator through the operations possible at each specific time, and to give instant visualization of changes in progress on the network. All operations are performed by the operator exclusively using the Mouse, which enables the choice of objects and commands in the on-screen Menus.
• the network diagram is managed entirely on-screen by several levels of visualization and the use of "Panning" commands for the positioning on the screen of the desired portion of the diagram.
• the MV network is managed by means of the following diagrams: General network diagram (figure 14).
• This schematic diagram which is contained in a single video page, gives a compact illustration of the whole network to be remote controlled, with a simple representation of all the Primary Substations in the Zone. Starting from this page, the operator can select one Primary Substation and request visualization of the topological diagram for the MV network around the substation selected.
• Topological network diagram (figure 15) .
• This schematic diagram shows all the secondary substations that are remote controlled, with their respective connections. It is generally an extremely large diagram, which cannot be shown in a single video page, but thanks to the "panning" it is possible to move through it in a continuous manner, visualizing any part of the chart.
• the topological diagram is the main working base for operation of the network. From this diagram it is possible to operate on the network requesting visualization of line and substation diagrams on overlying windows and so on.
• MV feeder diagram (figure 16) .
• This diagram which is obtained from the preceding one by highlighting the portion of network electrically connected to a specific MV circuit-breaker, is fundamental for feeder boundary changes, network adjustment, manual recovery of service following a fault or an unavailability period.
• the directrix At each point at which it is possible to reenergize a feeder power the directrix, all the information necessary for resupply actions is given.
• a suitable compacting algorithm it is always possible to obtain un-deformed visualization of the whole feeder line, even when the latter is greater than the screen size on the topological diagram.
• Feeder section diagram (figure 17) : As only remote controlled substations are shown on the topological diagram, it is necessary to have a further level of detail, which can be selected from the topological level. From this schematic diagram it is possible to update information on all the non-remote controlled secondary substations within a section. The aim of this diagram is to allow manual updating of the information relating to the status of switches that are not remote controlled.
• Primary Substation diagram (figure 18) : a window containing the typical schematic diagram of a primary substation with the HV/MV transformers, the bus-bars fed by them, and the connected MV feeders.
• the dynamic block automatically assigning the exclusive ability to operate on an electrical element to the first workstation selecting the command; the block operates from the moment in which the command is selected until it is completed or cancelled.
• Attribution of a feeder may be determined statically during configuration, or it may be established during normal operation.
• the alarms and variations in status that relate to both the MV network and the Primary Substations, are routed to the various workstations, by which they are acquired automatically or manually according to the working attribution; they are then printed on the "Service Protocol" and filed in the mass storage.
• the operator can access the diagram for the corresponding electrical element, and then perform whatever adjustment he desires.
• the operator can perform the following: request print-outs (in graphic or table form) , search the data base, search the back-up files containing past operating data.
• STM provides a series of automatic procedures aimed at identification and isolation of the faulty section of line between two remote controlled substations, the re-energizing of the section of the network upstream of the faulty section, and the possible re-energizing of the network downstream of the latter.
• the remote terminal unit devices have been designed with a high degree of autonomy (automatic rules for opening and closing the switches) , giving them the ability to identify and isolate a faulty section of line autonomously.
• the rules for opening the switch are activated on the basis of a lack of voltage on the line and on the bus-bar in a secondary substation, any failure in power supply to a Primary Substation MV bus-bar, should it continue for longer than the time limit set for activation of the above rules, causes the unnecessary opening of all the switches in the remote controlled substations powered by that MV bus-bar.
• the STM is provided with an automatic procedure which, following a loss of voltage on a Primary Substation MV bus-bar, sends a message disabling the automatic rules to all the UPTs involved within the necessary time limit.
• the STM automatically restores the initial status.
• the remote controlled secondary substations must be suitably equipped with voltage detectors (RV) and, in urban underground networks, with devices to sense the passage of fault current (RG) .
• the RGs to be installed on each cable terminal are made up of a toroidal probe, to be installed around the cable itself, capable of picking up the passage of homopolar currents (caused by phase to earth faults) of an intensity exceeding a certain predetermined level (typically 60 Amp.), and three "maximum current" probes, one for each phase, capable of picking up the passage of short-circuit currents exceeding a certain predetermined level (typically 600 Amp.) ; this information is passed through small cables and optical fibers to the electronic circuits which, in case of malfunction, cause an optical and an electrical signal (closing of a contact) to be emitted.
• a toroidal probe to be installed around the cable itself, capable of picking up the passage of homopolar currents (caused by phase to earth faults) of an intensity exceeding a certain predetermined level (typically 60 Amp.), and three "maximum current" probes, one for each phase, capable of picking up the passage of short-circuit currents exceeding a certain predetermined level (typically
• the UPT essentially gives a series of rules for opening and a series of rules for closing the switches.
• the opening rules have the aim of isolating the malfunction, whereas the closing rules serve to re ⁇ energizing the bus-bar in the secondary substation, thus restoring communication.
• Each switch is associated to a specific group of rules, which are univocally identified by the type of switch (incoming, outgoing, boundary) and by the type of network, overhead (without RG) or cable (with RG) .
• IMSi generic motorized load breaking MV line switch RVLi, voltage detector associated with the MV line originating at IMSi
• RVS voltage detector associated with the MV bus-bar to which IMSi relates
• the opening rules that apply for UPT without RG are the following:
• Ravi RVLi * RVS * beta > - if the IMS in question was closed with an autonomous command, it is opened first and then all the other IMSs on the bus-bar are opened.
• a group of rules Z (blockage of all IMS) is associated to all IMSs; - if the IMS in question was closed with a remote command, it is opened and the group of rules Z (blockage of that IMS) is associated to it.
• the condition beta occurs when the IMSi passes from the open state to the closed state in the presence of line or bar voltage, and the condition of lack of line or bar voltage occurs within Tavl seconds.
• the condition beta resets after a local or remote comand closing the IMSi.
• RcvO RVLi * RVS * TcvO * delta ,,,,> close IMSi
• Rcvl RVLi * RVS * Tcvl * delta ,,,,> close IMSi
• the condition delta occurs when all the IMS on the bus-bar are open.
• condition alpha implies that one of the following conditions has been met: the UPT receives no reply to the fault interrogation message sent to another UPT; the IMS whose RG has sensed the fault has no UPT associated with it.
• Rag2 RVLi * RVS * RGi * gamma , , ,> opening of all the IMS on the bus-bar starting from the one associated to the RG that sensed the fault current, and association of group "Z" to them.
• the condition gamma occurs when: the RG of all the IMSs, with the exception of the i-th IMS, have sensed the fault current; - the UPT has transm itted the message responding to the interrogation received from the preceding UPT.
• the closing rules that apply for UPT with RG are the following:
• RcgO RVLi * RVS * TcgO * delta ,,,,> close IMSi
• Rcgl. RVLi * RVS * Tcgl * delta ,,,,> close IMSi
• the condition delta occurs when all the IMS on the bus-bar are open.
• One of the following groups of rules can be associated to each IMS in an UPT with RG: - group "D”, made up of rules RagO, Ragl, Rag2 and RcgO group "E”, made up of rules RagO and Rcgl group "Z”, made up of no rules.
• the configuration message For each line IMS in a secondary substation, the configuration message must be sent to the respective UPT.
• This configuration message contains: the group of automatic rules to be applied, the address of the UPT downstream. Furthermore, the values of the opening and closing time constants must be configured for each UPT. Startup of the procedure
• STM When final tripping of the MV line circuit-breaker takes place, due to the intervention of one or more protections, STM starts a timer Tl, following which it commands the MV circuit-breaker to close. If this operation, which simulates slow re-closing, causes further tripping, then the procedure for sectionalizing faulty section starts. Sectionalizing faulty feeder section procedure overhead lines (without RG)
• STM commands closure of the MV circuit-breaker in the Primary Substation.
• Closure of the MV circuit-breaker has positive results; STM positions itself to await automatic closure of the IMS entering the first substation. When this takes place, connection between the system and the UPT resident within it is restored and the STM starts to re-close the first of the IMS on output from the substation; if no other remote controlled substation is connected to it, the procedure continues to re-close the other IMS adjacent to it on the bus-bar, until another remote controlled secondary substation is re- energized.
• the central System once more reverts to standby to await automatic closure of the IMS inputting to the substation.
• STM starts a new substation IMS closure cycle using remote commands.
• the MV circuit-breaker trips, and the IMS performing the closing on fault opens and blocks.
• STM re-closes the circuit-breaker and renergizes the feeder up to the section immediately upstream of the faulty one.
• the System by interrogating the UPT in the substation on which it was operating before the trip and by picking up the open and blocked status of the last IMS handled, emits the diagnostic relating to the faulty section. Then the automatic procedure goes on to re-energize any branches upstream of the fault that may still be without power. (If possible the automatic resupplying procedure is started) .
• STM By interrogating the latter (the UPT upstream of the fault) , STM recognizes that the IMS connecting the substation to the one downstream is closed as usual, so that it is not a section fault, which would have cause opening and block of the IMS, but a fault in the downstream substation bus-bar. STM emits the diagnostic relating to the faulty secondary substation bus-bar and the procedure goes on to re-energize any branches that may have been left without power. (If possible the automatic re-supply procedure is started) .
• the command to re-close which is emitted by STM subsequent to the last trip, prevents a transitory or semi-permanent fault that may occur on the feeder during the identification phase, from being mistaken for the permanent fault that has started the procedure.
• the STM finds no IMS in block mode, that is to say if no fault has been identified, the procedure continues by feeding the other sections.
• the above error would occur in the case of a transitory malfunction occurring within the time Tavl, which, however, is fairly short. It will now be illustrated an example of procedure for a permanent fault on section "c" of figure 21.
• Figure 21a shows a schematic diagram of the overhead network under consideration, energized under normal working conditions by substation CP1 through a MV circuit-breaker II.
• STM After a period of time T2 to ensure opening of all the IMS on the feeder (fig.21b) , STM sends a command to close II and awaits the result of it.
• STM commands closure of the first IMS in output (IMS2) and awaits performance of the remote command.
• the System interrogates the UPT again to check that the manoeuvre has been performed successfully, then, as IMS3 covers a remote controlled substation, the system starts a timer to await closure of the ingoing switch in CAB2.
• STM interrogates the UPT in CAB2 to check that the incomming IMS has been closed and to command closure of the outgoing one.
• STM awaits closure of IMSI of CAB6, and when this has occurred also closes IMS2 using a remote command.
• a waiting time is set up, during which the UPTs interrogate each other in cascade to identify the fault and open the IMS isolating it.
• the STM commands closure of the main switch and re-energizes the working sections of the feeder (unless the malfunction is in section I of the line) .
• Closure of the MV circuit-breaker causes instantaneous tripping of the latter; the System emits the diagnostic "Fault on first section” and terminates the procedure (if possible the automatic re-supply procedure is started) .
• Fault on an intermediate section Closure of the MV main switch, in this case, has a positive effect, and allows the STM to communicate with the UPTs and therefore to emit the signal indicating the section in which the malfunction has occurred.
• the interrogation sequence sent to the UPTs regarding the status of the various IMSs will underline a situation in which one switch is found to be open, whereas the same switch was not open just before the fault occurred. STM therefore emits a diagnostic identifying the fault on the section downstream of the above switch.
• Figure 22a shows the network under consideration, supplied under normal conditions by substation CP1 through the MV circuit-breaker II.
• the group of rultes associated with each IMS is indicated beside the graphic symbol, and causes them to behave as illustrated above.
• STM starts a timer with a duration Tl, following which the circuit-breaker will be re-closed (Fig. 22b) .
• UPT1 After a time Tin from loss of voltage, UPT1, which knows itself to be the first on the feeder, sends an interrogation message GI to the UPT downstream of the outgoing line on which the RG is in "on" state (UPT2) .
• UPT2 having received the interrogation message, responds with RGR, thus confirming the "On" status of one of its RGs. After sending the message RGR to UPT1, UPT2 in turn sends an RGI to UPT3.
• UPT3 which has no RG in "On", does not respond (or else the fault prevents transit of messages on the section) .
• UPT2 upon failing to receive a response, understands that the fault is on the section downstream of its own IMS2, opens it and sets it to blocked mode (Fig. 22c) .
• the IMS normally open
• the IMS which is the boundary between the feeder containing the fault and that adjacent to it, is provided with an automatic rule that causes it to close if there is a loss of voltage lasting for a determined period of time.
• closure of this IMS re-establishes data connection with the boundary substation and the consequent ability of the STM to re-energize all the working section of line downstream of the fault by an iterative process.
• the subsystem in question allows remote management of both LV and MV users, thus making it possible to carry out a series of operations that would normally be carried out on site by specialized staff.
• thermomagnetic circuit breaker to protect the upstream circuit (and to limit the maximum demand below the contractual value when the electronic unit is not installed in the meter)
• the electronic units are The electronic units.
• each meter For transmission of the consumption data indicated on the Ferraris meter to the electronic unit inside, each meter is provided with the following (figure 16) :
• each optical fiber is fixed in correspondence with the edge of the wheel, in a face- to-face configuration, whereas the other end is connected to the connector.
• the light beam generated by a photo-electric emitter installed in the electronic unit, is carried to the edge of the sector wheel through one of the two optical fibers, either passing through or not passing through the wheel, according to the position of the sectors.
• the main categories into which users of a generic electric utility can be divided are the following:
• thermo-magnetic circuit-breakers installed inside the GMY and GTY are original products, designed to satisfy the following needs:
• this value can be changed from a remote center following variation of the contract, emergency in the supply, etc. ;
• the circuit-breaker has been provided with a tripping coil which allows it to be controlled by the electronic unit.
• the electronic unit is the same both for the GMY and for the GTY, but it has been made in two different versions called UEP and UEPR (reduced UEP) .
• the UEP is used in an Integrated Metering Apparatus when the latter is installed inside the user's premises, whereas the UEPR is used in an Integrated Metering Apparatus when the latter is installed on a central board (on the same panel, which is usually situated on the ground floor of the building, it is possible to install up to 24 meters) .
• a central board on the same panel, which is usually situated on the ground floor of the building, it is possible to install up to 24 meters.
• the functions of the electronic unit are grouped in a single unit (UEPC) which performs these functions for all the apparatus on the board.
• the photo-emitter and the photo-receiver for generation and pick-up of the optical signals and the final relay to trip the circuit-breaker are the only components inside the UEPR, which is thus an extremely low-cost unit.
• Figures 20A and 2OB show how an UEP or an UEPR can be inserted from the back of a GMY, and how the GMY itself can be installed on the central board.
• Figure 21 shows a central board with an UEPC serving all the metering apparatus on the board.
• the current transformers required for the GTWS apparatus are the same for the whole range of use, from 30 to 250 kW; they are housed in the case illustrated in figure 25, on which the apparatus is installed by means of plug connectors.
• the above case houses four current transformers (TA) instead of the three that are strictly necessary (one TA is also inserted on the neutral conductor) in order to detect any fault that can be detected from the imbalance of the four secondary currents.
• the voltage and current transformers required for the GTWM apparatus use a single voltage ratio and four current ratios, and can be used to cover the whole field of use of the apparatus on ENEL's MV networks, with nominal voltages between 10 and 20 kV.
• the current and voltage transformers can be installed in two different types of housing: the first is an air-insulated compartment, the second is an SF6- insulated box (figure 26) .
• the air-insulated compartment comprises the coupling device for transmission of high-frequency signals from the electronic unit to the MV network, whereas in the SF6-insulated box this device is inserted externally by a plug connection, to allow easy replacement in case of malfunction.
• the electronic units used in these apparatus are the following:
• each ACS interrupts its background activity described above, and starts a new polling procedure consisting in the reading of data recorded by all the meters fed by a transformer, in order to acquire the following:
• the messages from the LV meters are temporarily stored in the ACS, from which they are then picked up by means of another procedure, parallel to the first one, carried out by the ACP on the ACS under it; the ACP in turn sends the data to the Central system.
• the latter retains the data with which it is concerned and, by means of the packet switching network, sends those relating to consumption to the Host Computer in the commercial department for invoicing.
• time of day tariffs by means of the new meters it is possible to apply time of day tariffs to all users, both LV and MV, and to carry out remote modification of the structure and parameters of these tariffs.
• Modulation of the power level available to the user by means of a suitable parameter K, which can vary between 0 and 1, it is possible to modify the power level available to the user, reducing it to a vital minimum level in emergency power supply situations, or even to zero if payments are in arrears or upon termination of contract.
• Remote modification of contractual parameters all contractual parameters, and in particular the set value of power can be modified from a distance.
• the latter converts the user identification code used by the Host Computer into the actual address used by the Distribution Automation System, then it adds the routing data on the basis of information continually updated by the STM.
• the message is sent to the meter, which confirms correct acquisition of the request; in exceptional cases on the LV network, the message might require a number of attempts before reaching destination, or it might even be delayed by several hours in order to await better conditions for transmission.
• Communication between the LV meters and the MV/LV substation causes a flow of signals which propagates on the wires and can be received inside the user's home through a special "User Terminal” (TU) .
• TU User Terminal
• the communication protocol together with the cyclic sequential polling, allows the channel to be shared by all the transmitters, that is by all the LV meters supplied by the same substation.
• the flow of information from the electric utilities is shown in a manner that is easily comprehensible to the user, and can be used for fairly sophisticated control of the load performed by the home Automation system. Furthermore, as the connection is potentially bidirectional, these services can be further extended.

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Citations (15)

• 1993
  • 1993-09-29 IT ITRM930660A patent/IT1261999B/it active IP Right Grant
• 1994
  • 1994-09-28 CA CA002170624A patent/CA2170624A1/en not_active Abandoned
  • 1994-09-28 EP EP94929621A patent/EP0721690A1/de not_active Withdrawn
  • 1994-09-28 BR BR9407683A patent/BR9407683A/pt not_active Application Discontinuation
  • 1994-09-28 WO PCT/IT1994/000158 patent/WO1995009473A2/en not_active Application Discontinuation
• 1996
  • 1996-03-29 NO NO961279A patent/NO961279D0/no unknown
  • 1996-07-15 FI FI962854A patent/FI962854A0/fi not_active Application Discontinuation

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