WO2018193272A1

WO2018193272A1 - System and apparatus for monitoring electricity supply system

Info

Publication number: WO2018193272A1
Application number: PCT/GB2018/051051
Authority: WO
Inventors: Hugh Smeaton
Original assignee: Hugh Smeaton
Priority date: 2017-04-21
Filing date: 2018-04-23
Publication date: 2018-10-25
Also published as: GB201914291D0; GB2577183A

Abstract

There is provided an electricity supply network provided to supply electricity to a plurality of premises and a method of assessing the. usage of the electricity, said premises provided with a meter capable of receiving and transmitting data relating to electricity consumption at the said premises, and wherein at least one meter is provided at a location intermediate the source of the electricity, typically at one or more substations. The premises meter is capable o f monitoring at least one parameter relating to the electricity supply at that said location and transmitting and/or receiving data relating to the same and comparison means are provided to allow data from the meters at the plurality of premises to be received and processed as a first set of data and compared with data received from the at least one further meter at the location upstream in the supply network.

Description

System and Apparatus for Monitoring Electricity Supply System

The invention to which this application relates is a system and apparatus which allows the monitoring of electricity supply systems and, in particular, to allow losses within the systems to be identified and thereafter acted upon to thereby allow a resultant reduction in electricity loss to be achieved.

It is known that in conventional electricity supply systems in the UK approximately 7% of electricity which is generated is lost and a higher percentage of loss occurs in other parts of the world, such as 30% of all electricity which is generated. The loss can occur, for example, through theft, by unauthorised tapping of the power lines.

In electrical networks, electricity is typically supplied in three phases, typically referred to as red, yellow and blue. Typically, for the relatively low level consumers such as domestic premises, the electricity supply to the premises is provided along a single phase as that can carry sufficient electricity for the demand from that type of premises. However, at present, there is no way for the consumer to be able to identify which of the phases is received and indeed, the different phases which are used to supply different consumers, is not currently controlled. This can lead to a phase imbalance in the network due to, for example, greater loads being placed on particular phases by connection of that phase to a number of consumers which is greater than the loads or demands on the other phases of the network by the consumers who are connected to one or both of the other phases. It is believed that this phase imbalance can cause problems in the control of the system operation as well as problems in other areas such as in terms of health, wherein if the phase imbalance is relatively large and may cause clusters of particular types of ill-health such as for example cancer. However, at the present time, the network companies do not have a means of switching phase supplies or indeed monitoring the level of phase imbalance.

In gas supply networks there is a need to monitor the supply of gas ate each, or groups, of receiving locations in order to ensure that the supply to the locations is acceptable and/or that theft of gas is not occurring from the network. The monitoring of this is most preferably achieved by the monitoring of the gas which is being supplied to the said locations.

There is an increasing demand from environmental bodies and governing bodies, as well as the generating companies, to reduce these losses both with respect to the financial and economic cost and also the environmental impact of generating electricity which is subsequently lost.

An aim of the present invention is therefore to provide a means of monitoring electricity supply within the supply network so as, firstly, to be able to identify that losses have occurred, and secondly to act on the losses with respect to the particular location of the same so as to allow the losses to be reduced.

A further aim of the present invention is to provide a means whereby the supply of a utility via a network can be monitored in an effective manner. One aim is to allow phase imbalance of an electricity supply to be controlled and, steps taken to adjust the network, in an informed manner so as to reduce phase imbalance and thereby allow the network to operate in a more efficient manner while, at the same time, ensuring that the supply to the consumer, is maintained. A further aim is to be able to efficiently monitor a gas supply network.

In a first aspect of the invention there is provided an electricity supply network, said network provided to supply electricity to a number of premises, and wherein at least one meter is provided at a location intermediate the source of the electricity and said premises and said at least one meter is capable of monitoring at least one parameter relating to the electricity supply at that said location and transmitting and/or receiving data relating to the same.

Typically said premises are provided with at least one meter capable of receiving and transmitting data relating to electricity consumption at the premises and the said at least one meter located upstream is a further meter in addition to those provided at the premises. Typically all of the meters are capable of transmitting data relating to the electricity consumption.

In one embodiment, comparison means are provided to allow data from the meters at the plurality of premises, to be retrieved and processed as a first set of data and compared with data received from the at least one further meter at the location upstream in the supply network.

In one embodiment, the location upstream is a substation and yet further, the meter is connected to one or more current transformers at said substation.

In one example, the substation is an 11000/415 volt transformer substation. In one embodiment, the substation is provided with twin transformers and meters are provided to allow the monitoring of and provision of data representative of the loads on each of the transformers. In one embodiment, if the identified load on one of the transformers falls below a predetermined level, then the said transformer can be switched off until the load on the remaining transformer is identified as exceeding a particular level. Typically the meter data is provided at given time periods so as to allow the operation of the transformers to be determined with respect to the particular loads at a given time.

In one embodiment, the comparison between the readings from the meters at the plurality of premises and the meters at the said one or more upstream locations, is performed continuously or, alternatively, at predetermined time intervals so as to allow a detailed record to be constructed of the electricity load at the respective meters at given times and/or to identify differences between the readings from a plurality of meters and the one or more meters at the upstream location so as to identify any electricity loss intermediate said meter locations and, if so, the extent of the loss and/or time of the loss.

In one embodiment, a plurality of meters are provided at a number of locations in the network upstream of the premises which are being supplied thereby allowing the network to be split into a series of sections, with at least some of said sections being monitored using the meter apparatus herein described and allowing comparison between meter readings to identify electricity loss in specific network sections.

In addition to identifying loss through theft, it is also possible in accordance with the invention to identify loss which is due to malfunction or poorly performing apparatus within the network and therefore identify the said components of the network which may need to be replaced.

In a further embodiment, the provision of the meters at the substation location, allows the occurrence and duration of unbalanced loading to be monitored and, if the same occurs over a prolonged period of time, the network operator can take action to reduce the unbalanced load and thereby reduce the loss which can be created by unbalanced loads due to the fact that the loss varies with the square of the current.

In a further aspect of the invention, there is provided a method of monitoring the performance of an electricity supply network, said method comprising the steps of obtaining data relating to the electricity supply to one or more premises by providing meter apparatus at said one or more premises, providing at least one further meter at at least one location upstream of said premises in the supply network, obtaining data from said further meters relating to the electricity supply at that location, comparing the first set of data retrieved from the meters at the premises with the second set of data obtained from the meters upstream in the network, and identifying differences between the said sets of data.

In one embodiment the comparison is made to identify whether electricity supply loss has occurred in the network intermediate the respective locations of the meters providing the first and second sets of data. In addition or alternatively the data in the first or second sets can be used to analyse and determine behavioural characteristics of the apparatus and/or electricity supply at the meter location.

The present invention therefore provides the ability for the electricity network operator to manage the demand for electricity and allow them to take action when electricity loss and / or supply malfunction is found to be occurring.

Thus, the meter apparatus at the location upstream of the premises in the electricity supply network is used to provide data relating to the identification of the phase of the electricity supply which is being monitored by that meter apparatus.

Typically, the phase identification occurs at a location which is either of a substation, a distribution pillar or link within the network.

The ability to identify the phase which is being monitored by a specific meter, means that the balancing of the load on the distributor feeding that single phase can be managed more accurately if the phase has been identified.

It should also be noted that any unbalances in the load between phases of the electricity supply, transfer upwardly from the location towards the grid in the network with not only increased losses in HkV feeders but in the transformers themselves.

Typically the network includes one or meters at a first location in the network to meter the electricity supply, and readings from said one or more meters are compared to the total of the meter readings taken for the supply of electricity to industry, commerce and/or households.

In one embodiment the said first location is as the system steps down from the national grid to the 33,000 volts substations.

In one embodiment the network includes a consumer 3 phase and single phase meter, a current multiplexer to measure currents from CT's and measure and log AC voltage and the time current and voltage crossover and wherein a plurality of district control processing means are provided to accept data from secondary sub-station meters located within the network and be capable of communication back to the sub-station meter.

In one embodiment the number of channels provided in the current multiplexer is selected with respect to the type of sub-station it will control. This unit will also measure and log AC voltage and the time current and voltage crossover.

In one embodiment the communication means between the sub station meter and the control processing means will be selected to suit the operating environment and/or network parameters. Typically secondary sub-stations do not have telephone lines and therefore some form of communication means may be required to be provided. One option is to use the same communication means as is used to communicate with the meter at the consumer premises.

In one embodiment there is provided a district control system for a district of an electricity supply network said system allowing analysis of the load flows in the llkV and 33kV networks to generate an audit trail of current and power factor through the network. Typically eth system also includes means to allow a control method to be used in conjunction with the date received from the meters at the substation to allow optimisation of the llkV switching for the supply network.

In one embodiment during planned or emergency load shedding, the method can be based on the actual load flows on the network together with the 24 hour history of load flows.

Conventionally, the network is open i.e. 11000/415kV sub-stations feed a dedicated number of secondary sub-stations and similarly a grid sub-station feeds a dedicated number of primary sub-stations. However the lack of current transformers (CT's) on 1 lkV switches means that full online data is not available to trace all load flows.

In one embodiment there is provided apparatus for use at a consumer location, said apparatus comprising a module for connection with the electricity supply at or adjacent to the consumer location, said module receiving a plurality of electricity phase supply cables on one side of the module and, at the other side of the module, one of the phase cables is provided to pass to supply electricity to the consumer location.

In one embodiment the module receives three phase supply cables.

In one embodiment the module also receives an earth or neutral supply cable.

Typically, the module is located prior to the fuses for the electricity supply at the said location.

Typically, the remaining two phases which enter the module but which do not leave the same, are terminated and retained within the module and access cannot be gained to the same for use.

Typically, the neutral or earth cable passes through the module to the electricity supply system within the consumer location and said system includes at least one meter which is located downstream of the said module.

In one embodiment, the module incorporates a means whereby an electrician or other qualified personnel can switch phases so as to select which particular phase cable leaves the said module to supply dectricity to the supply system in the consumer location. It will be appreciated that this therefore allows specific phases to be used to supply specific consumer locations and, thereafter groups of locations. A further possibility is that the said phases can be altered subsequently, after installation, to take into account the changes in the supply parameters which may occur as further consumer locations are added to that particular network portion or, once particular loadings of usage are identified so as to ensure that phase balance is rnaintained.

In a further embodiment, the module is provided with four incoming cable cores and receives the same in a terminal block The two cables which are to leave the module to connect with the electricity supply at the consumer location, are also terminated at a terminal block and links or switches are available within the module to allow the person, such as an electrician or other qualified personnel to choose the appropriate phase which is to be linked between the terminal blocks.

In a further embodiment, the module includes switching means, which typically are actuable externally of the module and which allow selection of an appropriate phase cable to be made and, in response to user operation of the switch, the appropriate phase cable can be connected to the outgoing cable to the electricity supply system. In this embodiment, an electrician or qualified personnel may not be required as no access to the interior of the module is required and thus, for example, the selection can be made by a person who is visiting a consumer location to read the meter.

In each case, it will be appreciated that the particular phase which is used to supply electricity to the consumer location can be changed at, or following and subsequent to, installation, thereby allowing adjustments to be made to the overall phase and balance value of the network or network portion over time.

In one embodiment, the alteration of the particular phase supply which is used may be made automatically by use of a data communication which is sent along the electricity network cables to the appropriate consumer location and to the module to cause a change to be made within the module in response to the data communication.

Thus, there is provided a method of addressing the power factor of an electricity supply network said method including the steps of placing power factor correction apparatus in the network, and assessing the power factor by the network provider.

In one embodiment there is provided a system for geographically locating the source of theft from a utility supply network

In one embodiment the data communication to the apparatus provided in the network is achieved using a power line carrier (pic) data system. In one embodiment for an electricity supply, a local Date Concentrator is fitted in the sub station supplying the consumers. This unit is P.C. based hence has ample computing power to handle the additional load of the losses monitoring system. In this embodiment a 3 phase unit is connected to the existing tdi current transformers at each substation and this is used to measure the current leaving the sub station, the voltage and the zero crossover time.

In one embodiment where there is not enough space for the LDC a custom housing is required to be provided.

In one embodiment the monitoring of the consumption is automated which, upon the detection of a fault or loss in the operation of the network which is beyond a predetermined level causes an alarm to be triggered.

In one embodiment, the alarm is a local alarm which occurs at the geographical location of the fault such as a substation or meter and/ or is an alarm which is activated at a remote control location.

Preferably, in addition to the alarm being generated, the system also analyses the fault which has caused the alarm and provides data indicative of the problem which has caused the fault

Typically, the data relating to the problem which has caused the fault, is sent to the network company or organisation which is in charge of the particular part of the network in which the fault is located.

It will therefore be appreciated that in one embodiment the alarm which is generated, can be from any part of a utility supply network within a particular geographical location such as a region or country and the identification of the fault is passed to a centralised control location or locations which will then identify the company or organisation responsible for that portion of the network in which the fault has been identified and pass data identifying the fault and preferably including the reasons for the fault, to the responsible company or organisation so that remedial action can be taken.

In one embodiment, there is provided a plurality of alarm conditions such as three alarm conditions. Typically, when any alarm is triggered, the system automatically looks at the network, such as for an electricity supply network the five distributors in the network system, and analyses the conditions of these to locate the problem or fault

In one embodiment, a mimic or representative diagram can be used to represent the network and which will show the loads and distributors of the network which can then be analysed and a report produced to identify the problem areas.

In one embodiment, in the case of a theft the report can give a geographical location of the theft together with the evidence to support the same.

In a further aspect of the invention, there is provided an electricity supply network, said supply network having a number of branch connections to domestic and/or industrial consumers and, intermediate the source of the electricity and said consumers, a plurality of substations at which the voltage of the network changes so that the electricity supply, once it reaches the industrial and/or domestic consumers, is in the required form, said domestic and/or industrial premises provided with a meter to meter the consumption of electricity and wherein each of the meters is provided with an identity which allows the readings data therefrom to be identified and wherein the identity of the sub-satiation which feeds each of a group of meters is known and an assessment is undertaken as to the level of electricity supply which should pass from each sub-station to the meters and compared with the meter reading data received from the consumer meters in the group supplied by said sub-station.

In one embodiment, the meter reading data is transmitted to a processing means such as a computer which is able to identify the particular meters from which the data is supplied and also data is received from the substation as to the electricity to be supplied to the consumers in a given period of time.

In one embodiment, the given period of time is 30 minutes and therefore data is received from the sub-station as to the expected electricity consumption in the next 30 minute interval and readings are obtained from the consumer meters at 30 minute intervals. The same would apply for other predetermined periods of time.

Typically therefore the processing means will total the energy consumed by the group of consumer meters fed from a particular sub-station as the readings from the predetermined time period are logged and the substation meter will provide data for the same predetermined period of time of the minimum energy it expects to be consumed by its consumers. If the calculated total is less than the predicted value this will indicate a loss of electricity and further analysis can be performed.

In one embodiment, the sub-station is provided with at least one meter and the meter will monitor the phase imbalance and VARS at the sub-station and, should the same go above preset levels, further analysis can be performed.

Typically, there is provided a means of allowing a three phase voltage supply to the sub-station, to be dealt with by the substation meter. In accordance with the invention, this is achieved by providing, at the sub-station, a 13 amp point and that, plus a three phase wedding ring CTS is fed into the meter. The meter then measures the time for the cross over of the 240 volt input (the blue phase) and the blue phase current and then measures the times for the crosses over of the yellow and red phases in turn and in the same manner. Thus, by taking into account the standard time for these phases to pass zero the phase angles of the yellow and red currents with regard to the blue phase can be calculated and, as a result, the monitoring of the electricity supply fed into the meter can be achieved.

In electricity supply networks there are a plurality of sub stations at which the voltage level of the electricity supply is changed for ongoing distribution downstream.

In substations provided for the reduction of the voltage from 415 to 240 volts is that unless the currents in all three phases are equal the cable copper losses in the system increase. In accordance with the invention, there is provided apparatus for allowing the current to be controlled and monitored and thereby allow the potential for copper losses in the system to be reduced.

In substations for larger voltages in the supply network, such as those for 11000 to 415 volts, there are thermal demand indicators fed by current transformers fitted onto the lower voltage output of the transformer.

In accordance with the invention there is provided an electricity supply network in which the voltage of the supply is reduced at sub stations as it passes through the network, said network including at least one substation in which there is provided at least one thermal demand indicator fed by one or more current transformers and wherein the output from the same is supplied to a to feed the output of these into a tdi replacement unit.

In one embodiment the current is stepped down to a lower level using a wedding ring contact

In one embodiment the voltage to supply the unit is provided from a 13 amp service point and in one embodiment this is also the reference voltage for the sub station.

In one embodiment the unit is equipped with a microprocessor and a pic modem and the phase angle of the two currents not associated with the supply voltage shall be established by measuring their cross over time relative to the known voltage.

In one embodiment a 3 phase voltage sensor with an onboard pic modem shall be developed and one each of these will be fitted in the first section pillar or link box fed by each distributor fed from the sub-station.

In one embodiment if a 3 phase branch is available before the first junction box it can be fed from its cut outs and/ or single phase units can be fitted to single phase branches and the phase connection established at that time to ensure all three phases of each distributor are measured. In a further aspect of the invention, there is provided an automated monitoring system which, upon the detection of a fault or loss in the operation of the network which is beyond a predetermined level causes an alarm to be triggered.

Preferably, in addition to the alarm being generated, the system also analyzes the fault which has caused the alarm and provides data indicative of the problem which has caused the fault

It will therefore be appreciated that in one embodiment the alarm which is generated, can be from any part of an electricity supply network witiin a particular geographical location such as a region or country and the identification of the fault is passed to a centralised control location or locations which will then identify the company or organisation responsible for that portion of the network in which the fault has been identified and pass data identifying the fault and preferably including the reasons for the fault, to the responsible company or organisation so that remedial action can be taken.

In one embodiment, there is provided a plurality of alarm conditions such as three alarm conditions.

Typically, when any alarm is triggered, the system automatically looks at that the five c-istidbutors in the network system and analyzes the conditions of these to locate the problem or fault

In one embodiment, a mimic or representative diagram can be used to represent the network and which will show the loads and distributors of the network which can then be analyzed and a report produced to identify the problem areas.

In one embodiment the network has a number of branch connections to domestic and/or industrial consumers and, intermediate the source of the electricity and said consumers, a plurality of substations at which the voltage of the network changes so that the electricity supply, once it reaches the industrial and/or domestic consumers, is in the required form, said domestic and/or industrial premises provided with a meter to meter the consumption of electricity and wherein each of the meters is provided with an identity which allows the readings data therefrom to be identified and wherein the identity of the sub-satiation which feeds each of a group of meters is known and an assessment is undertaken as to the level of electricity supply which should pass from each sub-station to the meters and compared with the meter reading data received from the consumer meters in the group supplied by said sub-station.

Typically, there is provided a means of aUowing a three phase voltage supply to the sub-station, to be dealt with by the substation meter. In accordance with the invention, this is achieved by providing, at the sub-station, a 13 amp point and that, plus a three phase wedding ring CTS is fed into the meter. The meter then measures the time for the cross over of the 240 volt input (the blue phase) and the blue phase current and then measures the times for the crosses over of the yellow and red phases in turn and in the same manner. Thus, by taking into account the standard time for these phases to pass zero the phase angles of the yellow and red currents with regard to the blue phase can be calculated and, as a result, the monitoring of the electricity supply fed into the meter can be achieved.

In one embodiment there is provided a processor located in a sub station with onboard PLC and GSM modems or a radio link. With this basic unit it is possible to monitor and control any or any combination of utilities in the form of electricity, water, gas and/ or street lighting.

Specific embodiments of the invention are now described with reference to the accompanying drawings wherein; Figures 1 and 2 illustrate, schematically, part of an electricity supply network in accordance with an embodiment of the invention;

Figure 3 illustrates a three phase supply layout;

Figure 4 illustrates an embodiment of an electricity supply system at a particular consumer location; Figures 5a and b illustrate embodiments of network control display screens.

Referring firstly to Figures 1 and 2, electricity is provided along the power line 4 in the network section shown from a generating location 6. The electricity is carried along the grid 9 to a substation location 8 which, in one embodiment, can include first and second transformers. Also, in accordance with the invention, there is provided metering apparatus 10, the form of which will be described subsequently. From the substation, the electricity supply is stepped down in voltage as shown in Figure 2 and distributed via power lines 12, 14, 16, 18, 20 to premises 22, 24, 26, 28 as shown in Figure 1. In accordance with the invention, each of these premises 22-28, are provided with metering apparatus 30.

The metering apparatus 10, 30, is provided of a type which allows data to be transmitted from the metering apparatus, typically via a power line carrier system, to a processing facility to provide data which is indicative of the electricity supply such as, for example, measuring the load. Typically, each metering apparatus is capable of receiving data and transmitting data, with the data, most typically, being carried along the power lines 12-28 and/or power line 4 to and from the processing facility. Typically, each of the meters will record the kilowatts per hour and input voltage values of the electricity supply at that location.

A meter interface unit can also be provided which allows relays, typically 15 amp relays, to be provided to allow load shedding circuitry to be connected to the meters as required.

The metering apparatus 10, at an upstream location such as the substation 8, is typically capable of providing three phase monitoring of the electricity supply with, again, power line carrier communication being used and will be capable of logging the current, voltage and phase angle of the supply from the substation along power line 12.

The processing facility (not shown) is capable of transmitting to and receiving a first set of data from the meters apparatus 30 and a second set of data from the meter, 10 and processing the received data and comparing the data from the respective meter locations in the network to identify discrepancies in the electricity supply between the said locations.

The supply network with which the invention is used is, in one embodiment, an l lkV ring network which can cope with 5MW of load. As, in accordance with the invention, the electricity supply coming out of the primary substations is metered in, for example, half hour recording periods, then accurate load distribution monitoring of the supply is possible. Thus as a result of the invention, the loading of the l lkV network can be monitored to indicate locations where the network is not operating correctly and requires upgrading and/or the identification of where uneven loading amounts between substations and/or at different periods of the day can be identified so as to allow the more accurate and efficient management of the operation of the substations to meet the variations in load due to demand variations at given time intervals.

In one embodiment, the measurement of the phase angle in the substation or other location means that it is necessary to take all three phase voltages to the substation meter apparatus. Due to high volt levels in the substation, for safety reasons, a single phase supply unit is preferable. However, in the instance that three phases are provided these phases can be identified electrically in the meter at the upstream location and this data can be transmitted to the connected meters at the premises such that each meter at each premises, can recognise the particular phase that it is being supplied by. This data can also be transferred to the processing facility to thereby allow the data for meters supplied by each particular phase, to be collated and then compared with the data for that specific phase collated from the meter at the location upstream.

High voltage faults are often easy to find and fix. However faults in the distributor line to premises, such as households, are often difficult to find and can lead to premises being without power for many hours or days while the fault is located and repaired. In accordance with the invention in one aspect the meters at the second location such as the premises locations are provided with triggers which detect when the power supply falls below a certain level, say 200 Volts, which is indicative of a fault having occurred. When this is detected the meter will start to log the voltage supply over time.

In practice the meters which are closest to the substation on the distributor or branch supply line will have the highest of the detected voltage levels and the detected voltage levels in subsequent meters located away from the substation will drop, typically successively. However the meters which lie on the branch line downstream of the location of the fault will not detect a drop in voltage and so reference to the detected voltages at the respective metets will allow the identification of the location of the fault along the distributor line as lying between a meter with a detected voltage drop and the next meter which has not detected a drop. This therefore allows fault location to be more quickly identified. Typically the electricity which leaves the 11,000/415 volt substations in the network comes out in four core cables which connect to the transformers via fuses. There is typically 415 volts between the three phases (red, yellow, blue) and 240 volts between any of the three phases and the neutral, as a fourth conductor is referred. This is illustrated in Figure 3.

Industry and other relatively large consumers are typically provided with a three phase supply, whilst households and lower users typically receive a single phase supply. Large electrical motors are all operated with a three phase supply while small motors such as fridge and deep freezers are single phase operated.

In one embodiment the losses which are identified using the method of the invention are transformer losses. In one embodiment the particular area of interest is with regard to those substations which have two transformers. In accordance with the invention by detecting the amount of electricity which is consumed at specific times it will be possible to selectively operate one or two of the transformers, with, for example only one transformer being connected to the 11KV network in times of low use, such as summer, as opposed to the present where both transformers are operated all the time regardless of the electricity usage at that period of operation. However losses on a normal 1000KVA transformer are 25KW i.e. £2.50 per hour at domestic rates which represent significant expense in terms of lost revenue. It should also be possible to carry out similar savings on the 33/11KV transformers with larger savings, but of course there are much fewer of these.

In one embodiment if the substation meters fed from the primary supply are coded in the same way as the meters at the premises then this allows the identity of the loading along the network.

In another embodiment power factor losses are identified in accordance with the invention. Where the connected load to the network at the user's location is electrical heat or filament lighting the power factor or efficiency is 100%. However when the load is an electric motor or a transformer such as those used by PC's, printers, scanners etc this efficiency can drop. In industry or large commercial premises it is normal for the electricity supply company to measure the power factor and charge the user on this basis. However the exact method of charging varies from one supply company to another. The power factor at the grid metering is 0.95-0.96.

Dependent on how the power factor is measured at the gird substations this may provide the full picture. It is normal to compute the power factor with reference to KWH and KVARH and theses values can be averaged every half hour and the half hour averages averaged over 24 hours. For example if it is applied in the same way as high users voltage metering and averaged over a month this approach will mask errors as there is a considerable off peak space and water heating load overnight when the rotating industrial load is low and this will distort the power factor calculations.

In a further embodiment of the invention the unbalanced loads in the network are identified. When the current carried in the three phase conductors is balanced then no current flows in the fourth or neutral conductor and this is known as a balanced load but this only happens with say three phase motors and never happens on the electricity network. Even in industrial or commercial installations, the load taken from the network is never balanced. However at present there is no way of being able to identify what this level of unbalance actually is as present metering does not measure or record the loads on the individual phases of the supply. In most cases the single phase domestic load is connected to the same distribution cables hence a balanced load on the distribution cables and substation transformers is not only never balanced but not measured in the substation. As an example if there is provided a load of 100 amps on the red phase, 200 amps on the yellow phase and 300 amps on the blue phase of a supply this will give an average load of 200 amps. However the losses of a 200 amp balanced load would be 200² = 40,000R x 3 = 120.000R.

However in the practical situation of the load being unbalanced, the unbalanced losses would be 100²R + 200²R +300²R = 10,000R + 40,000R + 90,000R = 140.000R i.e. an increase of 16.66%. In addition, further losses occur in the neutral conductor plus an unbalanced load increases the losses in both 11KV and 33KV networks and transformers thus leading towards potential losses of approximately 20%. The provision of metering at the end user and at at least one location further upstream as well as the metering of the each of the phases would allow the unbalanced load losses to be identified and actions taken to balance them.

There is therefore provided a solution to the problem by providing a network management system for the supply network which include an integrated metering system using intelligent meters at consumer locations and at at least one location on the network upstream from said consumer locations.

In one embodiment, in an industrial situation, there is provided metering for a three phase supply which logs at predetermined time intervals, such as half hourly intervals, the KW on all three phases on the supply and the voltage and power _; factor on all three phases. Typically the current in each phase is either measured or alternatively calculated from the other readings. The meters are provided with a data communication system such as a Power Line Carrier (PLC) system to allow data representative of the readings to be transmitted to a monitoring location. At household premises, a single phase meter can be provided to measure a voltage current and phase angle and record these at predetermined intervals, again such as half hour intervals. Once more a data communication means is provided to allow the data to be transmitted to a monitoring location.

In one embodiment the single phase meter can have two output ports to allow it to command remote connection and disconnection of two 15 amp circuits. The meter typically will also have an electronic address which will relate to the distributor and substation that feeds it.

As part of the network, the substation can be provided with a three phase meter which is used to measure phase voltages, phase currents and phase angles on each phase. It typically has an electronic address and PLC communication capability to a landline or mobile phone interface.

In one use of the invention there is provided a network monitoring control system provided to operate at a district level so that each meter in the system shall be electronically addressed to the substation feeding the meters. Typically the monitoring method allows the following to be identified by the monitoring means:

1. The load on the substation at predetermined time intervals which will allow transformers to be switched off in twin transformer substations during summer periods and only brought back on when required. 2. By totalling the consumer meter readings and comparing to the substation readings, the network losses in each substation can be calculated. In the case of stolen electricity, the time of theft will be known within a predetermined time period and, by looking at the voltages down the distributor from consumer readings, it should be possible to close in on the source and location of theft.

3. The profile of the voltage readings will allow close analysis of copper losses and also atomise the interconnections of the 415/240 volt network in towns and cities. By checking the power factors at both consumer and substation locations, it will be possible to determine the degree of the problem and take up with the consumers who are identified as creating the problem.

In the case of phase unbalance, loads can be moved in industrial and commercial premises. With domestic consumers premises, loads can be "swung" into blocks of flats with three phase supplies and/or ground supplies can be shifted by jointing.

As loads vary, full time monitoring may not be attractive but the monitoring of substations on an annual basis would be of use. With regard to the ll KV network, there needs to be metering installed within the same and typically, in each primary substation with the meters therein tied into the secondary substations which are fed by the primary substations. This could help to optimise network upgrades and/or handle major faults which occur.

Similarly with the 11KV or 415V distributors the system can be used to quickly establish the scale and location of the fault and also check that everyone is supplied once again once the fault has been located and repaired. In one practical embodiment in a network each consumer is provided with a meter with a unique serial number together with an electronic address required for metering purposes. When the meter is connected to the network it broadcasts a message to its host sub-station to identify itself and of course the phase that it is being fed from and then sends out data at regular intervals, say ½ hourly readings. The host sub-station stores this data for a period of time, typically chosen by the network operator, such as a 24hr period.

The documentation for meter reading purposes is sent to the associated network company who logs this data into the district controller. From existing records the district controller now knows the geographical location of the meter hence the distributor that feeds it This means that between the host sub-station meter and the district controller, the geographic location of the meter, the distributor that feeds it and the actual phase for single phase meters is known. Ideally this data should be fed by the district controller to a mimic diagram that identifies the distances between sub-stations and consumers. Thus data is important in terms of using data to help optimise network upgrades or automate LV fault location. An alternative option is to quantify distance and cross-section area of cables between consumer and sub-station at the time the consumer is logged onto the system

The invention therefore allows the provision at the substation of at least one meter which knows the power, phase angle and phase load of every consumer fed by the substation, at regular time intervals such as every half hour. The meter then totals the load registered in the consumer's meters in terms of kW, PF and consumer's voltage. It then summates the consumer's data and compares this to the energy leaving the sub-station every half hour and has pre-set trigger points, such as

1) If the difference between energy recorded on consumer's meters and that sent out falls below pre-set levels either in total or specific half hourly periods.

2) Phase imbalance not only in terms of quantity of phase imbalance but the length of time it runs. 3) Power factor and variations over the preset log time.

4) If consumer's voltage falls or rises above preset limits (i.e. loss of neutral).

5) Load patterns equivalent to illegal usage patterns such as in terms of cannabis farms can best be identified in meters at the sub-station so as to more quickly help locate them

In practice if the district control gets an alarm from a sub-station meter it can interrogate the meter and download its readings. As it knows the location of every consumer on each phase, the loads drawn and the voltages at each consumer's meter this data can be used to help locate not only excess losses but the time they take place.

With regard to phase imbalance this can come from 3-phase consumers or un-balance from single phase consumers. The phase imbalance will vary over the length of a 3-phase distributor and also over time.

There is no possibility of ever getting anything like even phase imbalance and of course load patterns will vary with time. However the system provides all the data required to help improve the situation by tariffs to three phase consumers, balancing loads by switching in such as blocks of flats. It will be an on-going process with the usual law of diminishing returns.

With regard to power factors the system can accurately locate in terms of value the power factor, the source of poor power factor and the length of time it runs

Primary and Secondary substation metering can be achieved by a multiplexer reading across inputs from the yellow phase and Rogowski coils on the protection CTs. As the input to the primary is from delta wound transformers to get kWH figures it requires a 2watt meter method. This can successfully be done at the multiplexer and can be easily done by feeding raw current voltage and crossover time to the area computer. Primary substations have mostly telephone line communication and can be run online or on a dial up basis.

In addition to the above uses the provision of the meters at the substations in accordance with the invention allow the monitoring of consumer voltage at the remote ends of networks to allow transformers to run on tap2 during summer periods when windmills could be toiling. This of course saves energy in terms of losses and generation. In addition, fault location can be more quickly achieved such as for example, with a 1.6 rating power factor, 400 amp fuses at the substation seldom blow instantaneously. The specification calls to time stamp voltage dips. The sub-station meter or district computer can use the voltages from consumer's meters along a distributor to help locate distribution faults.

Thus the provision of meters with communication means at substations and particularly secondary substations allows processing means to build up a picture of network loads by summating the loads on secondary substations to build up the loads on primaries. At the end of the day the system allows the network company to trace every amp entering the system to its eventual destination. It will identify the source of network losses and if both primary and secondary substations are quipped in accordance with the invention all or the majority of losses on the network can be traced and identified.

In the embodiment shown in Figures 4-5b there is illustrated part of a utility supply system which can be provided at a particular consumer location and the same includes a meter 102 which is required to monitor the level of utility usage by the consumer and from the meter, although not shown, cables or pipes will lead to allow the distribution of the utility throughout the consumer location.

In the case of an electricity supply network, upstream of the meter there is provided an input cable 104 which includes a fuse or cut out 106 in a conventional manner and this cable provides electricity to the meter and hence to the consumer location. There is also provided a neutral or earth cable 108 in a conventional manner as well as the contactor wires 110.

Upstream of the cables 104 and 108, there is provided a module 112 in accordance with the invention and this module includes input cables comprising a neutral cable 114 which connects through, or is continuous, to cable 108 , and three phase supply cables marked red,R, yellow,Y, and blue, B respectively. Typically, the module will be provided at each consumer location and is capable of allowing a selection of one of the three phase cables 110, 112, 114, to be connected internally of the module 112 to the downstream cable 104 and hence provide the electricity to the consumer location. In the particular example shown, the red phase cable is connected to the cable 104. However, in accordance with the invention, it should be appreciated that although for example, the red phase supply is connected at the time of installation, ongoing monitoring of the phase and balance value of the supply network to a number of locations may indicate, for example, that the red phase is out of balance with usage on the other of the phases. Thus, in accordance with the invention, the particular phase which is used to supply the particular consumer location cable 104 can be adjusted subsequently, either by an electrician visiting a consumer location to make the alteration within the module, altering the particular phase in response to the usage of a switch device provided on the exterior of the module or alternatively, a data communication is passed to the location along the electricity supply network to cause the module to react to the data communication and to switch the phase connection within the module to the particular phase which is identified in the data communication.

Thus, the present invention can be utilised to ensure that the phase imbalance is minimised at any given time of operation of the electricity network to one or a group of consumers.

Figures 5a and b illustrate examples of display screen formats which may be used by a network provider in monitoring the performance of the network. Referring firstly to Figure 5a there is illustrated a sub-station layout of the network with the Kw, Kvar and current output leaving the sub-station indicated. There is also illustrated the total of the meters fed by the sub station showing the total Kw, Kvar and amps. Below that are the 5 distributors of the network and these will show the totals of readings of Kw, Kvar and current on each phase. This is possible as as each meter on the network is logged onto the system it gives its serial number to the substation meter and the meter installer gives the location in terms of names and addresses of the relevant meter serial number. On that basis the following is known.

1 Total losses in terms of Kw

2 Total Kvars leaving the sub station

3 Value of current leaving sub-station

4 Total Kwh taken by consumers on each phase

5 Total current taken by consumers on each phase

6 Total Kvars taken by consumers take by on each phase

The distributors show the individual phases and how they equate to sub station totals. The vars is illustrated as coming from computed values of kw. current and voltage from consumer meters in the sub station (s-s) meter. This provides to the network provider the full picture of the loads, their source and characteristics plotted geographically on the representation of the whole length of a distributor. From this the losses can be calculated in every different length of cable and the source of the losses

An alarm trigger is operated when the output rises but no rise occurs in the meter usage total and the relative phase but not the distributor supplying the electricity to the part where the theft is occurring. Each feeder can be shut down in turn to locate the feeder with the theft problem. In the event of an alarm the s.s meter will request instantaneous readings from all meters and feed this data onto the Figure 5b display format.

Figure 5b represents a distributor and shows all three phases and the geographical location of every branch. As the distributor is typically 400 metres long it runs along more man one street and changes cross section area from the sub station to its end. All of this data will be shown in detail by roll out or zoom in techniques, the street lengths and geographic locations of branches shall be accurately scaled onto the line drawing. Single phase branches will be shown by a small circle and 3 phase by a large circle and the Kw, current, voltage and kvars when used. Thus the source of low power factor and phase imbalance can easily be seen to allow corrective measures to be taken. Separate displays can be generated for theft, phase imbalance and power factor. Theft can be alarmed as described earlier and by computer scanning the cumulative loads down the distributor, the line impedance taking into account the cable cross section area and consumer voltages down the line it should be possible to get a close location of the problem. A three phase external input channel can be provided to the s-s meter to allow split ring cts. to be attached to an individual distributor as the system only shows the transformer losses. In most cases the volt drop method will pick up the theft and the external drive is provided as a back up. This approach can also be used to trigger the alarm and give a location of the theft and automatically identify the distributor.

Using similar methods of voltage measurement down the distributor it is possible to give fault location between two branches, and by monitoring the voltage at the end branches decisions to allow possible transformer tap changes to be made.

The method described can be used as the basis of tracing load flows from grid input through 33 and 11kv networks to consumers. This information is vital in minimising disruption during load shedding.

With regard to pf and phase imbalance, both where they occur along the length of the distributor and the length of time they last are important as the copper loss is I squared R T and we can calculate R from the cable cross section area and the relative cable length. From mis, data losses in terms of Kwh can be calculated and decisions taken on how to reduce losses. In one embodiment this data is integrated into proposals to reduce losses from p.f and phase imbalance so that network operators have the cost of every source of loss together with the costs of reducing these losses and can take cost based decisions. Thus a meter at the ss can log the Kw, current and voltage and kvars from consumers will be calculated in the ss meter. In one embodiment it is possible to overlay the network representation onto a digitised map so as to provide the geographical locations of the various components of the network portion which is being monitored and thereby allow the location of a fault or theft to be identified with reference to the map.

By providing the network distributor details on a graphical representation such as digitised map and the geographic locations of network branches added, then a clear picture emerges of the network in terms of the sub station, the distributors fed from it and the branches connected to the relative phase on each distributor. To this can be added the cross section area of the distributors and any long branch cables and this data is held in the Local distribution company (LDC) rather than a District control computer as before. The software now uses the scale of the digitised map together with the impedance of the relative cables gained from their cross section area to convert from relative length to impedance between branches on each phase and from branches to sub station.

With this data in place and all meters connected to the branches a picture emerges of the source and nature of the loads on the network coming from consumers and this can be compared to the loads leaving the s/ s fed from the s/ s meter into the LDC. The LDC will log this data for a preset period, say one week, and start to roll the data over beyond that period. Starting at the remote branch on each distributor the system will build a picture of the current build up on each phase of each distributor until it reaches the substation and using the impedance between each branch establish a theoretical voltage at each meter as it increases as it nears the substation.. Due to manufacturing tolerances on meter accuracy the system will calibrate the meters relative to one another for the purposes of monitoring but not for billing purposes. There is therefore provided a network distribution and monitoring system which has the capability to approach losses in the network in the following manner.

With regard to theft an alarm will be triggered when the difference between the total energy recorded on consumer's meters in any period of time, such as half an hour, drops below the energy leaving the substation in the same period by a preset value. When the alarm occurs the system will examine the difference in the volt drops between adjacent meters in terms of actual and theoretical and when a voltage has changed with no increase in associated current the potential fault has been located. The LDC sends the alarm to a remote Network Control Centre to examine the evidence from the LDC, verify there is theft taking place and inform the network operator or, if there is not a clear indicator, will increase the frequency of readings from the meter until a decision is taken as to the validity of the alarm Where theft is taking place it is possible to run the system for a period to place a value on the theft or choose a time to investigate.

With regard to the power factor, with metered data on smaller network supply systems, such as that of Glasgow University's Lv. network averaging 0.8 thus increasing copper losses by at least 56%, monitoring is possible. From the metering data corning from meters a value is established for the kvarhs drawn from each distributor and logged onto the system. Once again an alarm is initiated when figures go above preset limits either on a half hourly basis or over a longer period such as a 7 day logging period and the data analysed. The system will show the value of the kvarh, it's location and the length of time it runs on the network and from this data and cable impedances the actual cost in terms of copper loss on the distributor can be established. By controlling power factor correction from consumer's meters or locating controlled correction along the distributor at optimum positions it is possible to totally remove p.f. as a source of loss increase. This holds for the Lv. network but as the voltage increase in the higher voltage networks cable and line capacitance become an issue and low carbon generation will complicate the matter. It was always envisaged to meter the llkv feeders leaving primary substations and once this is carried out a clearer picture -will emerge and it is possible the optimum situation for the network in total is a small lag but these proposals allow network operators to totally cost and run p.f at a level to suit themselves.

With regard to phase imbalance it should be recognised that phase imbalance is magnified by power factor. Similar to power factor while it will vary over a period of time such as 7 days it will settle into a pattern. Similar to power factor the costs of phase imbalance can be established simply on the Lv. network and with more difficulty on upper voltage and negative phase sequence problems in transformers.

The above covers the approach to tackling network losses but reducing losses is only one benefit of the system.

It should be noted the improvement herein described reduces the number of District control centres to just a few. Not only does this reduce the cost but the fewer people involved means greater expertise in tackling the problems. The system allows the tackling of tosses and an audit trail of energy leaving the grid through to every consumer. In addition to the above investigations have shown that with the llkv network " running open " the system at present traces the loads from the llkv side of the primary to the consumer. If the same applies to a 33kv network out of a grid substation and it also runs open , then the audit trail is complete. With that in place in the event of shortage of generation capacity or loss of a major s/s it is possible to allocate energy to every consumer.

In an electricity supply network, typically from a one or more generating locations to one or more consumer locations the voltage is stepped down in terms of its size at a plurality of substations as it passes through the system such that, for example, in the UK the voltage when it reaches domestic consumer premises has a value of 240 Volts which is significantly lower than that at which the supply started.

In accordance with the invention at a substation in the network, and typically a substation for the relatively lower voltage levels, the voltage from each distributor branch will be fed to a substation monitor together with the relative distributor identification. The cable distance from the substation to the branch shall be established and converted to impedance as the cross section of the relative cable is known.

As a result of knowing the voltage between the points and the impedance, Ohms Law allows the currents to be calculated. The system can be calibrated by software in the unit taking into account any known errors in the voltage sensors or discrepancies in distance measurement by measuring the actual currents leaving the substation at the time of commissioning. Accuracy can also be checked by totalling the individual distributor loads and expressing each as a percentage of the transformer load.

A modem can typically be provided to transmit the data to a control centre and a display fitted or external entry to allow for calibration at the substation.

The invention as herein described therefore allows losses in the system to be minimised as the monitoring of the supply at the substation allows the current balance to be maintained.

In another example of use , if the utility network is a gas supply network, there is a need to monitor the pressure of the gas supply at each or groups of end users in order to determine whether eth gas pressure is at the required level in order to indicate a "normal" and expected supply level. If the pressure is found to be lower than expected then is indicative of a fault or possibly theft of gas occurring upstream of the location at which the gas pressure is monitored. In accordance with one embodiment of the invention there is provided a portion of gas supply pipe upstream of a supply outlet and at which there is provided a means of measuring the pressure of gas passing through the said pipeline and a communication means for transmitting data indicative of the measured gas pressure to a remote location.

The basic problem is to measure and transmit the gas pressure at the nearest point of monitoring the distribution pipe line. Preferably this is performed as near as possible s at the fuel user location. As the gas meter is fitted after the regulator a new design of meter capable of handling the higher pressures prior to feeding the regulator would be one route but this is impractical.

Another option, as described previously, is to use the pipe that exists between the cut off valve and the regulator and the solution to the monitoring problem is to replace that pipe with one connected to a pressure sensor interfaced to a PLC modem. In one embodiment the pressure transducer can be an integral part of the pipe fed directly into the modem with the dectricity supply coming from an instrument fuse on the live side of the meter.

With this monitoring apparatus fitted at entry and exit points of the distribution pipe line the device could be provided in a portable format and once a leak on a pipe line has been thought of as a possibility the device can be progressively fitted long the pipe line until the source of the pressure drop is located. This provides the following benefits.

1 Using Electricity sub stations distribution as the basic geographic layout it is possible using the portable approach to trace major leaks in the system.

2 By fitting them permanently in the system at entry and exit points in the not only is it possible to trace existing leaks but new ones as they occur.

The comparison between the input to any area and the metered usage over the same time period should give an input to the level of theft as the pipe line has already been checked for leaks. By fitting Pressure Pipe monitoring devices at every consumer on the distribution line theft can be eliminated. Once the Pressure Pipe monitoring device is fitted the consumer cannot modify a meter as the unit will immediately alarm loss of pressure. In volume these Pressure pipe monitoring devices will be relatively cheap and by using PLC the one modem can be used.

In one embodiment the communication means is a PLC transmitter. In one embodiment the monitoring means and the PLC transmitter are provided as a unit along with the length of pipeline and the same is then retrofitted to the gas supply pipe to replace an existing portion of the gas supply pipe.

Typically the portion which is replaced is a flexible pipe which is located between a gas flow regulator and metering apparatus.

Typically the data which is transmitted to the remote location can be transmitted continuously or at predetermined intervals. Typically the data is analysed to indicate whether the detected gas pressure is wilbin predetermined parameters and, if not, an alert is generated to indicate irregularity of the gas pressure at the location from which the data was received

Starting with electricity a first stage move is to fit wedding ring cts onto the 1500/5 TDI cts and feed those into the P.C so that it knows the current drawn from the transformer. By using single to three phase voltage conversion it is possible to calculate the phase angle of all three phases hence a TDI replacement is provided which is capable of alarming high phase imbalance and low power factor and outage via the GSM modem or radio link. It acts as a Sub Station Meter capable of measuring the transformer output in KWH , KVAh and KVARH.

To phase out the meters as they are installed as described previously a known load can be switched at intervals and the P.C software recognises the phase this load is coming in on and gives the handshake back to the meter hence both Networks and Supply have a record of the meter connection. If PLC is chosen for metering communications the meters download their metering data once or twice per day via the PLC modem where the data is stored prior to sending out via the GSM modem to the invoicing platform. The unit has now replaced the LDC in a PLC based system.

With regard to network losses, the processing means, which may include software totals the metered consumption over a given period and comparing with the energy supplied by the transformer feeding the meters over the same period. If the loss figure goes above a preset limit an alarm is raised to trigger the relative action. This P.C is idle rtinning these applications.

With regard to gas supply the system in accordance with the invention gives at least two potential input terminals to help manage the network and possibly also street lighting and a domestic meter with an on board pressure sensor. This meter would not be fitted as standard but simply at points in the network at which monitoring is required. With these two input points and a duplex modem at the street lighting, the gas supply and street lighting management are in full control of their network as the electricity supply which is required to power apparatus is the supply network, such as motors etc also carries the instructions to control them.

A similar system can be utilised for the supply of water .

With regard to the tracing of Utility Losses, digitised Maps are referred to of the geographical area covered by the monitored network or networks with a loss of electricity and or pressure in other utility supply networks used to help locate the loss. It is up to gas and water engineers to establish the connection if any exists but all three have a common element i.e., they only require one digitised map which can again be held in monitoring apparatus of the invention.

In one embodiment, with regard to electricity, the effective control area via processor located at a substation is of the order of 600m diameter round the s/s which will need to be changed for gas and water appEcations. Each Utility will have their own digitised map covering larger areas and the local map in the monitoring apparatus will merge edge to edge to make up the larger unit in the utility control centres to ensure no drop in accuracy during drill down

The only electrical connection between the Smart Meters and the Grid in the network distributions systems is the Secondary 1000 KVA Substations that convert the electricity from 11,000 volts to 240 volts and each supplying on average 400 single phase consumers. The energy supplied is split over 3 phases with one 11,000 volt 3 phase cable supplying 50 amps/phase to the Substation Transformer. The Transformer converts the 11,000 volt 50 amp energy to just under 1400 amps at 240 volts to feed six three phase Distributors supplying the new single phase Smart Meters ie each Distributor on average supplies 66 consumers split over 3 phases or 22 consumers/phase. Network Losses are governed by Ohm's Law which decrees as the current doubles the losses quadruple. Thus Network Losses are of the order of 780 times greater in the Low Voltage Network than the 11 Kv network when supplying a fully loaded 1000 KVA [Kilo volt amp] Transformer.

Before reducing avoidable network losses, the system in accordance with the invention measures them by installing a Substation meter and then by employing the half hourly readings from the Consumer Meters the losses from each Secondary Substation are calculated. Tracing these losses to 400 consumers is a process of eHtnination such that if a consumer's meter can recognise onto which phase of the six three phase distributors the consumer has been connected, the odds drop from 400-1 to 22-1 and is it is possible in accordance with the invention to establish the geographic location of the consumer's meter on the relevant distributor, so the data produced by the Meter can trace the location of Electricity Theft or cable faults. The PLC sends the data from the Meters via a Local Data Concentrator located at the Secondary Substation to a central resource induding an invoicing platform and it is then a matter of extracting the data and comparing with the data from the transformer meter at the relevant substation.

The PLC is introduced into all three phases of the electricity supply via a LDC which acts as a centralised data source sending and receiving data to known addresses. Preferably the LDC is located close to the Transformer via a 3 phase branch thus the high frequency goes through the transformer distribution pillar bus bars and out on all 3 phases of each distributor cable. Thus every consumer location has an 1/ O. terminal with a known address, including the LDC and Transformer Meter.

This allows a 3 lane 2 way communications system highway to be created which for ease of illustration are referred to herein as Red, Yellow and Blue lanes. Data flows along each of the lanes and each terminal is aware of which of the lanes their data is travelling. Both Consumer and Transformer meters will address their data to the LDC for onward transmission via land line or wireless communication to pre designated addresses. The data produced relates the metering data to the particular meter locations on the digitised maps used by network engineers. This process therefore enables the system to trace all network electricity losses including those caused by theft, by measuring the current and its direction in any distributor, and also to alarm and localise distributor faults as they occur and these measurements can be made to measure the losses in any length of distributor on which the PLC is established.

In order to measure and locate the losses from a Transformer all consumers meters relate their readings to the host transformer.

Thus in accordance with the invention the system tackles the key point of identifying which of the three phases the existing consumer's branch cable is connected to and thereby makes it possible to measure or trace the losses on a 3 phase 4 wire system. Subsequent to that idmtification the voltage drops that occur on the low voltage can be analysed and by applying Ohm's Law, the currents flowing in the low voltage cables can be calculated. This then allows those consumers whose meters are not recording the energy they are using to be identified and/or it can be identified where energy is being extracted from the network at locations where no consumers are known to exist

In one embodiment the substation meters are provided to measure the electrical energy leaving the Substation at regular time intervals, such as every half hour. These meters are installed directly onto the secondary of the TDI CTS or via wedding ring CTS. These meters are typically powered from the 13 amp service socket in the Substation and so will not require connection to the Substation Bus Bars. In order to measure the losses from the network supplied by the Substation then preferably all consumer meters supplied by the Substation shall be read over the shortest possible period and these readings are compared to the average of die Substation Meter half hourly readings over the same period. On that basis an accurate estimate of Network Losses can be obtained, together with analysis of the current leaving the Substation.

Typically the system in accordance with the invention will be scalable. For example, for use in larger networks the phase angle effect of the current flowing in the Network can be taken into account as any phase angle, leading or lagging, increases the Network Losses. However as the phase angle is based upon a cosine curve it is not economical to correct the lagging Power Factor above 0.87.

In one example of use then for a conventional 0.3 sq. inch Distributor cable, the same carries 400 amps. If it is assumed that at no load on the Distributor 1 Kw [4 amps] of electricity is stolen then the losses on that length of distributor according to Ohm's Law are 4x4= 16 R where R is the resistance of the one Distributor phase. If the same 4 amps is stolen when the Distributor is carrying its peak load of 400 amps the losses become 404x404 = 163216 R which is at the extreme end of the spectrum but, in order to avoid Power Cuts the generation capacity has to carry the Peak Load including Network Losses. The average Power Factor is typically around 0.8 which would push the losses by 56%. Peak loads tend to fall at the end of the day with both commerce and industry creating a lagging Power Factor.

Maintenance requirements can be met on a "plug and play " basis with no work carried out on site. The c.t input will plug into the monitoring apparatus which acts as a "hub" via a 6 core plug with shorting links at the c.t end to ensure the cts do not go open circuit during installation and any maintenance change. In one embodiment the monitoring apparatus can also effectively monitor itself and automatically report faults to the relevant control centre.

Typically the monitoring apparatus is a P.C with an A/D converter to accept inputs from the transformer TDI cts. and PLC input and GSM or radio output both units typically being duplex. It offers the following with regard to electricity in the automatic phasing out of existing meters when connected, it allows the profile of both phase imbalance and power factor of the energy leaving the s/s with regard to electricity. Also, once all the meters are fed from one s/s it is a simple matter to calculate losses and trigger alarms once data values go above preset limits. With regard to gas supply there is provided the basis of managing the gas supply network to reduce losses and the same applies with regard to street lighting. Collection of relevant data from the meters can be achieved by the installation of relevant processing means software.

Once installed, a geographic picture will emerge of the loads on the electricity network. However where the 33kv network is run open by linking together the sub stations fed from the primary one, the monitoring apparatus at the "Master" Sub Station can collect the data from the rest of the substations and send to Control or Control can access directly. If the 33kv network runs open the link between Grid and Distribution has been established with an audit trail of every amp leaving the grid through to every consumer which would offer a whole new level of control during supply shortages leading to confining Load Shedding to History Both Gas and Water networks span greater areas than that covered by a secondary sub station, however by using the sub station as the core of their system and the same digital maps used to trace electricity theft it may be possible to use the basic system to build a geographic picture of their load profiles.

The system utilises the provision of meters to monitor the usage of electricity at the consumer locations and at the substations in the network from which the electricity is distributed to the consumers. The system includes the installation of meters at the substations and the subsequent analysis of data from the respective meters allows the performance of the network and potential losses, and the location of die system in the network, to be identified.

Claims

1. An electricity supply network, said network provided to supply electricity to a plurality of premises, said premises provided with a meter capable of receiving and transmitting data relating to electricity consumption at the said premises, and wherein at least one meter is provided at a location intermediate the source of the electricity and said premises and said at least one meter is capable of monitoring at least one parameter relating to the electricity supply at that said location and transmitting and/or receiving data relating to the same and comparison means are provided to allow data from the meters at the plurality of premises to be received and processed as a first set of data and compared with data received from the at least one further meter at the location upstream in the supply network.

2. A network according to claim 1 wherein the upstream location is a substation and the said further meter is connected to one or more current transformers at said substation.

3. A network according to claim 2 wherein the substation is an 11000/415 volt transformer substation.

4 A network according to claim 2 wherein the substation is provided with twin transformers and a said further meter is provided to allow the monitoring of, and provision of data representative of, the loads on each of the transformers.

5 A network according to claim 1 wherein the comparison between the readings from the meters at the plurality of premises and the said further meters at the said one or more upstream locations is used to construct a record of the electricity load at the respective meters at given times and/or to identify differences between the readings from a plurality of meters and the one or more further meters at the upstream location so as to identify any electricity loss intermediate said meter locations and, if so, the extent of the loss and/or time of the loss.

6 A network according to any of the preceding claims wherein there is provided a consumer 3 phase and single phase meter, a current multiplexer to measure currents from current transformers (CTs) and measure and log AC voltage and the time current and voltage crossover and wherein a plurality of district control processing means are provided to accept data from secondary sub-station meters located within the network and be capable of communication back to the meter at the sub-station.

7. A network according to claim 1 wherein at the premises there is provided a module for connection with the electricity supply at or adjacent to the consumer location, said module recdving a plurality of electricity phase supply cables on one side of the module and, at the other side of the module, one of the phase cables is provided to pass to supply electricity to the consumer location, the remaining two phases which enter the module but which do not leave the same, are terminated and retained within the module and a neutral or earth cable passes through the module to the electricity supply system within the premises and at least one meter is located downstream of the said module.

8. A network according to claim 7 wherein the module incorporates a means whereby an electrician or other qualified personnel can switch phases so as to select which particular phase cable leaves the said module to supply electricity to the supply system in the premises.

9 A network according to claim 7 wherein the alteration of the particular phase supply which to be used is automatically achieved by use of a data communication which is sent along the electricity network cables to the module at the particular premises to cause a change to be made within the module in response to the data communication and select the particular phase.

10 A network according to any of the preceding claims wherein data communication to and from the apparatus provided in the network is achieved using a power line carrier (pic) data system.

11. A network according to claim 10 wherein a local Data Concentrator unit is fitted in the sub station supplying the premises.

12 A network according to claim 11 wherein a 3 phase unit is connected to the existing transmission and distribution interface (tdi) current transformers at each substation and used to measure the current leaving the sub station, the voltage and the zero crossover time.

13 A network according to any of the preceding claims wherein the network includes an automated monitoring system which, upon the detection of a fault or loss in the operation of the network which is beyond a predetermined level causes an alarm to be triggered at the geographical location of the fault such as a substation or meter and/or at a remote control location.

14 A network according to claim 1 wherein the network has a number of branch connections to domestic and/or industrial consumers and, intermediate the source of the electricity and said consumers, a plurality of substations at which the voltage of the network changes so that the electricity supply, once it reaches the industrial and/or domestic premises is in the required form, said domestic and/or industrial premises provided with a meter to monitor the consumption of electricity and wherein each of the meters is provided with an identity which allows the readings data therefrom to be identified and wherein the identity of the sub-satiation which feeds each of a group of meters is known and an assessment is undertaken as to the level of electricity supply which should pass from each sub- station to the meters connected thereto and is compared with the meter reading data received from the meters in the group of premises supplied by each respective said sub-station.

15 A network according to claim 14 wherein a three phase voltage supply is provided to the sub-station and data relating to the same is generated by a meter at the substation which is provided with a 13 amp point and a three phase wedding ring Current Transformers (CT's) which are fed into the meter which measures the time for the cross over of the 240 volt input (the blue phase) and the blue phase current and then measures the times for the crosses over of the yellow and red phases in turn and by taking into account the standard time for these phases to pass zero the phase angles of the yellow and red currents with regard to the blue phase can be calculated and, as a result, the monitoring of the electricity supply fed into the meter can be achieved.

16. A method of monitoring the performance of an electricity supply network, said method comprising the steps of obtaining data relating to the electricity supply to one or more premises by providing meter apparatus at said one or more premises, providing at least one further meter at at least one location upstream of said premises in the supply network, obtaining data from said further meters relating to the electricity supply at that location, comparing the first set of data retrieved from the meters at the premises with the second set of data obtained from the meters upstream in the network, and identifying differences between the said sets of data to identify whether electricity supply loss has occurred in the network intermediate the respective locations of the meters providing the first and second sets of data and/or analyse and determine behavioural characteristics of the apparatus and/or electricity supply at the meter locations.

17 A method according to claim 16 wherein the said further meter at the location upstream of the premises in the electricity supply network provides data to identify the phase of the electricity supply which is being monitored by that meter apparatus and thereby allows balancing of the load on the distributor feeding the identified single phase.

18 A method according to claim 16 wherein one or more meters at a first location in the network provided data for consumption at that location and which is compared to data taken for the supply of electricity to industry, commerce and/or households and the first location is as the network steps down from the national grid to the 33,000 volts substations.