2.Overview Section

A1700 Programmable Polyphase Meter

Chapter 2 - Overview

M120 001 2S

5.2007

A1700 Chapters Chapter 1 Introduction M120 001 1 Chapter 2 Over view M120 001 2 Chapter 3 Hardware M120 001 3 Chapter 4 Communications M120 001 4 Chapter 5 Input/Output M120 001 5 Chapter 6 Installation M 120 0016

Chapter 7 Software Support M120 001 7 Chapter 8 IEC 870 Meter (Special) M120 001 8 Chapter 9 T. L. Compensation (Special) M120 001 9

A1700 Meter Users Manual - Chapter 2 1 ______________________________________________________________________

CONTENTS

1 POWER AND ENERGY MEASUREMENT ............................................................................ 2

2 PRINCIPLES OF ENERGY MEASUREMENT ....................................................................... 3

2.1 Energy Measurement .............................................................................................................. 3 Figure 1 3-Phase 4-Wire System .......................................................................................... 3 Figure 2 3-Phase 4-Wire Vector Diagram............................................................................. 3 2.2 Apparent Energy Measurement .............................................................................................. 4 2.3 Reactive Energy Measurement ............................................................................................... 4 2.4 Four Quadrant Metering .......................................................................................................... 5 Figure 3 Four Quadrant Measurement.................................................................................. 5 2.5 Network Application................................................................................................................. 5 3-Phase 3-Wire ....................................................................................................................... 6 Figure 4 3-Phase 3-Wire System .......................................................................................... 6 3-Phase 4-Wire ....................................................................................................................... 6 Figure 5 3-Phase 4-Wire System .......................................................................................... 6 2-Phases of 3-Phase 4-Wire ................................................................................................... 7 Figure 6 2-Phases of a 3-Phase 4-Wire System................................................................... 7 1-Phase 3-Wire........................................................................................................................ 7 Figure 7 1-Phase 3-Wire System ......................................................................................... 7 1-Phase 3-Wire........................................................................................................................ 8 Figure 8 1-Phase 3-Wire System ......................................................................................... 9 1-Phase 2-Wire........................................................................................................................ 8 Figure 9 1-Phase 3-Wire System ......................................................................................... 9

3 TARIFF APPLICATIONS........................................................................................................ 9

3.1 General .................................................................................................................................... 9 3.2 Tariff Features ....................................................................................................................... 10 Billing Date ............................................................................................................................ 10 Billing Period.......................................................................................................................... 10 End of Billing Period .............................................................................................................. 10 Time of Use Registers ........................................................................................................... 10 Switching Times .................................................................................................................... 10 Seasons................................................................................................................................. 11 Integration Period .................................................................................................................. 11 Average Demand................................................................................................................... 11 Maximum Demand ................................................................................................................ 11 Block Interval Demand .......................................................................................................... 11 Sliding Window Demand ....................................................................................................... 11 Cumulative Registers ............................................................................................................ 12 Cumulative Maximum Demand ............................................................................................. 12 Total kVAh ............................................................................................................................. 12 Customer Defined Registers ................................................................................................. 12 3.3 Time Keeping ........................................................................................................................ 13 3.4 Data Logging ......................................................................................................................... 13

4 CONFIGURATION, COMMUNICATION AND DATA COLLECTION.................................. 14

4.1 General .................................................................................................................................. 14 4.2 Support Systems ................................................................................................................... 14 Figure 10 Total System Capability ........................................................................................ 14 Power Master Unit Software.................................................................................................. 15 CHIRPS ................................................................................................................................. 15 Figure 11 - CHIRPS Overall Concept.................................................................................... 16

Elster Metering Limited - M120 001 2S - 5/2007

2 A1700 Meter Users Manual - Chapter 2 ______________________________________________________________________

Overview

1 POWER AND ENERGY MEASUREMENT Electrical Power in any system of n conductors may be measured by the algebraic sum of (n-1) wattmeters. This is known as Blondel's Theorem. It derives from the fact that the power in each of the conductors is measured with a current sensor that determines the current, and a voltage sensor, which measures the potential of the conductor relative to a common point.

If the common point of the voltage measurement is made one of the conductors, one of the wattmeters will read zero and can therefore be omitted.

If the word "power" is replaced by "energy", "wattmeter" by "watt-hour" meter, the theorem is applicable to energy measurement.

In the A1700, analogue to digital converters, fed by sensors, determine the voltage measurements. These replace the conventional current and voltage coils of electromechanical meters.

There are some installations where (n-1) meter elements are not used. For economical and installation reasons, forms of watt-hour meters having fewer than (n-1) meter elements are considered satisfactory where the compromise still permits metering accuracy well within good commercial practice. For example, in some cases it is assumed that the voltages are approximately balanced. In others the load is assumed to be connected only between certain wires.

If a system is grounded and the ground lead not connected into the service installation, the ground still constitutes one of the n conductors. For example a 3-phase 4-wire system with earth neutral may be used at some location with only the three phase wires. Applying the theorem to the metering service, it must be considered as a 4-wire system.


Overview 3 ______________________________________________________________________

2 PRINCIPLES OF ENERGY MEASUREMENT

2.1 Energy Measurement The principles involved in measuring energy using the A1700 meter can be described by considering a 3-phase 4-wire circuit. Figure 1 shows a typical arrangement for a CT operated meter.

A1700

Va VcVb

Ia

Ia

Ib

Ib

Ic

Ic

Za

Zb

Zc

A

B

C

N The vector diagram (Figure 2) shows the relationship between the phases. Note: safety earths are omitted

Figure 1 3-Phase 4-Wire System

Figure 2 3-Phase 4-Wire Vector Diagram V

A IA

, VB

IB

and VC

IC

are phasors representing sinusoidal quantities.

The total power at any instant is given by: P = va ia + vb ib + vc ic, where v and i are instantaneous values at time t, and the total energy is the integral of power with time.


Expressed mathematically this is:

T2

E = Pdt T1 The current and voltage waveforms are close to being sinusoidal and the more well known expression for power is given as P = VAIA cos A + VBIB cos B + VCIC cos B CV and I are the r.m.s. values of voltage and current = Phase displacement between them.

The way in which the meter derives its power measurement is to measure digitally at discrete intervals the voltage and current on each phase. The product of these measurements and the period of the discrete time interval give the energy value. These discrete energy values are accumulated into a total energy register. This is sometimes referred to as the real energy measurement and is registered Watthours or kiloWatthours.

2.2 Apparent Energy Measurement A quantity often required for tariff purposes is apparent energy or Volt Amp hours (VAh). Apparent energy is derived by multiplying the r.m.s. voltage and the r.m.s. current values together, then integrating over time to produce VAh.

The A1700 meter uses the same digital measurements used for the real energy to derive the r.m.s. voltage and current and hence the apparent energy. The Volt-Ampere measurement is a scalar quantity. Strictly, it has no relation to phase displacement between voltage and current. In some tariff applications it is necessary to register the Volt-Amperes in one quadrant.

2.3 Reactive Energy Measurement An important measurement often required as part of the energy measurement is the reactive component. This relates to the phase difference between the voltage and current waveforms.

At unity power factor i.e. when the current and voltage are exactly in phase, there is no reactive energy. At zero power factors, i.e. current and voltage are 90 phase displaced, all the energy is reactive, there is no real power recorded.

The reactive power, or out of phase power, is often defined as VI sin where V and I are the r.m.s. values of voltage and current, and is the phase displacement between them.

Unlike electromechanical meters, where the standard technique is to cross connect the voltage coils, the A1700 meter performs this function digitally. The reactive energy is calculated on a phase basis from the simultaneous measurement of apparent energy and real energy. This achieves a more accurate measurement, being a true sine measurement, and it has the advantage of being applicable to both single and polyphase systems.


Overview 5 ______________________________________________________________________

2.4 Four Quadrant Metering The measurement techniques for real and reactive energy employed in the A1700 meter rely on sampling the voltage and current waveforms and multiplying these values together with the time interval. The measurements are independent of the phase angle and can therefore take place through a phase difference of 360 between voltage and current. This effectively provides 4-quadrant energy metering.

Real and Reactive energy are identified as being import or export. In the case of reactive energy the terms lag and lead are often used. The meter identifies in which quadrant the reactive energy is relative to the real energy, and accumulates the consumption in a particular register. It is therefore capable of measuring:

Q1 kvarh Import Lagging Energy Q2 kvarh Import Leading Energy Q3 kvarh Export Lagging Energy Q4 kvarh Export Leading Energy

The relative positions of these are as shown in the figure below.

Figure 3 Four Quadrant Measurement

2.5 Network Application Polyphase meters in general contain either two or three measuring elements. The number of measuring elements a polyphase meter has is determined by the network to which it is to be applied.

The following are examples of the more common applications in power networks. For other applications, contact Elster Metering Systems.


2.5.1 3-Phase, 3-Wire Two element meters are used for applications with line to line voltage applied across the voltage sensor and line currents through the current sensor. The circuit and vector diagrams are shown below.

VAB

VBC

VA

VAB

VCB

VC

IA IA

IB

ZAB

ZCB

ZAC

IC

IC

IA

A

B

C

1

2

Figure 4 3-Phase 3-Wire System P = VAB IA cos (30 + 1) + VCB IC cos (30 - 2)

2.5.2 3 Phase, 4 Wire In a 3-phase 4-wire system, three elements are required for accurate measurement. This equates to three single phase meters. The circuit and vector diagrams are shown below.

VAN

VBN

Ic

IA

IB

IA

IB

ZA

ZB

IC

VCN

A

B

C

N

VAIA

IC

VC

VB

C

Figure 5 3-Phase 4-Wire System P = VAN.IA.cosA + VBN.IB.cosB + VCN.IC.cosC


Overview 7 ______________________________________________________________________

2.5.3 2-Phases of 3-Phase, 4-Wire

In a 2-phases of a 3-phase 4-wire system only two elements are required for accurate measurement. The circuit and vector diagrams are shown below.

VANVAN

VCN

VCN

IA

IC

IC

IC

IA

IA

ZC

ZA

A

C

N

N A

Figure 6 2-Phases of a 3-Phase 4-Wire System P = VAN.IA.cosA + VCN.IC.cosC

2.5.4 1-Phase 3-Wire This is sometimes used in systems where a single phase supply has a centre tapped neutral. The circuit and vector diagrams are shown below.

VAIN

VA2N

IA1 IA1

ZA2

ZA1

IA2

IA2

A1

N N

A2

VA1N

VA2N

IA2

IA1

A1

A2

Figure 7 1-Phase 3-Wire System To meter a 1-phase 3-wire circuit with maximum accuracy under all conditions, it is necessary to use a two element meter. The A1700 meter uses a 2-element measurement for this application.

Power measurement in r.m.s terms is:

P = VA1N. IA1. cosA1 + VA2N. IA2. cos A2


2.5.5 2-Phase 3-Wire This system is used where two phases have a common neutral. The circuit and vector diagrams are shown below.

VAIN

VA2N

IA1 IA1

ZA2

ZA1

IA2

IA2

A1

N N

A2

VA1N

VA2NIA2

IA1

A2

A1

Figure 8 2-Phase 3-wire P = VA1N. IA1. cosA1 + VA2N. IA2. cos A2

2.5.6 1-Phase 2-Wire Single phase measurement can be achieved in the A1700 meter using only one element of the three elements available.

VAIN

IA1 IA1

ZA1

A1

N

N

VA1N

IA1A1

Figure 9 1-phase 2-wire

P = VA1N.IA1.CosA1


Overview 9 ______________________________________________________________________

3 TARIFF APPLICATIONS

3.1 General Tariffs link the consumption of energy to the cost of supplying it. In simple cases the cost per unit (kWh) is at a flat rate throughout the billing period. In other cases, the cost per unit varies according to the time when it is used. For these applications the A1700 meter has many programmable features, which allow consumption to be registered for different times of the day. The registers associated with this are termed Time of Use (TOU) or rate registers. In the A1700 meter there are options of 16 or 32 registers available for this purpose. They can be designated to record kWh, kvarh, kVAh or external inputs if an input module is fitted.

In addition to Time of Use, Maximum Demand is a measurement that is often applied for tariff purposes. The Maximum Demand is the largest demand occurring in a demand period during the billing period. Typically the demand period is 30 minutes or 15 minutes. It is also referred to as the integration period. In the case of a 30 minute demand period the average demand of electricity defined in kW is twice the number of units (kWh) registered in the period. For 15 minute periods it is four times. The billing period is the time between the successive issuing of accounts, typically one month. The maximum demand is recorded in the A1700 meter for any of the specified measurements, kW, kvar or kVA. The time and date of occurrence is also recorded, and there are up to 8 MD registers that can be used. These are programmable so that, if necessary, the maximum demand can be separately defined for different time of use periods.

There are two ways in which the MD can be derived, block interval or sliding. When computed by the block interval method the demand values are compared for successive integration period and the highest value registered. For example the periods would be 00.00, 00.30, 01.00 etc.

The alternative method, sliding demand, looks at a 30-minute period that moves throughout the day as a window. There is a minimum slip time that must be specified to give 10 or 15 minute blocks within the window.


3.2 Tariff Features 3.2.1 Billing Date

The Billing Date is the date that concludes the current billing period for use in the customer account. All the consumption during the period is transferred to historical registers for checking during the succeeding period. There is a specific time when the end of the billing period occurs, usually 24.00 (midnight).

3.2.2 Billing Period

The Billing Period is the time between consecutive Billing Dates.

3.2.3 End of Billing Period

The End of Billing Period defines the time and date when consumption data is recorded for the Billing Period. In the A1700 meter this action can be initiated in the following ways:

By a pre-programmed date and time stored in the meter

By an external input pulse to one of the meter module inputs

Over a communications link through the serial port

Through the optical port

By pressing the sealable push button

At a change of season date

At the introduction of a deferred tariff

3.2.4 Time of Use Registers

The A1700 has the option of 16 or 32 Time of Use registers. These registers become active or inactive when a pre-programmed time and date is reached. When active, a designated measurement, kWh, kvarh, kVAh or pulses from an input module (if fitted) is accumulated into the selected register. The accumulation continues for the active periods during the Billing Period.

The meter must be programmed to set Time of Use registers active in accordance with the requirement of the tariffs. More than one Time of Use register can be active at any one time.

3.2.5 Switching Times

Switching times define the times of the day when Time of Use registers become active and inactive. These times are resolved, usually to a 30-minute or 15-minute period i.e. the integration period.

The meter has the capacity to store 96 switching times. It is possible to have different tariff arrangements for different days of the week e.g. weekday and weekend tariffs.


Overview 11 ______________________________________________________________________

3.2.6 Seasons

Tariffs schemes can vary for different periods of the year. A period of time defined by a start date and an end date identifies a season in which a tariff arrangement applies. This may include daily variations. The A1700 has a maximum of 12 Seasons.

3.2.7 Exclusion Dates During a Season there may be specific days such as public holidays on which a different tariff arrangement applies. These days can be programmed by identification as an exclusion date within a season. There is a maximum of 64 Exclusion Dates.

3.2.8 Integration Period

The Integration Period is the time in which the demand is determined. Usually this is 30 minutes or 15 minutes, but can be any integer devisable in to 60 minutes.

3.2.9 Average Demand

This is the average power consumed in the Integration Period. It is computed by dividing the energy consumed (kWh, kvarh, kVAh or recorded input energy) by the Integration Period in hours.

3.2.10 Maximum Demand

The Maximum Demand is the highest demand recorded for the specified parameter, kW, kvar or kVA, during the Billing Period. The A1700 meter can record up to 8 Maximum Demands. For each of these, in some versions, the second and third highest are also recorded.

Maximum Demand can be recorded in two ways, Block Interval and Sliding Window.

3.2.11 Block Interval Demand

The Block Interval Demand is the calculation of the demand in non-overlapping integration periods e.g. 30 minutes.

3.2.12 Sliding Window Demand

The calculation of demand averaged over an Integration Period which includes sub-intervals of previous demand calculations, e.g. a 30 minute demand period with sub-intervals will be defined as 09.00 to 09.30, 09.10 to 09.40, 09.20 to 09.50 etc.


3.2.13 Cumulative Registers The Cumulative Registers are the total register reading of the primary values:

kWh import/export kvarh in four quadrants Q1 kvarh Import Lagging Energy Q2 kvarh Import Leading Energy Q3 kvarh Export Lagging Energy Q4 kvarh Export Leading Energy KVAh Input pulses

Regardless of which Time of Use register is active, the Cumulative Register will always advance.

3.2.14 Cumulative Maximum Demand

At the end of a Billing Period the Maximum Demand is added into a register. This is the Cumulative Maximum Demand.

3.2.15 Total kVAh

kVAh is a scalar quantity and is calculated from the total kWh and the total kvarh over all phases. (See Figure 3).

For some particular tariff applications it is required to determine the kVAh by using customer defined quantities. The quadrants to be used in kVAh calculation can be selected by the user. e.g.

Q1 Q2 Q3 Q4

kWh * *

kvarh * *

Note: Real and reactive energy for each phase is respectively summated prior to kVAh calculation.

3.2.16 Customer Defined Registers

The quantities to be calculated are selectable by 3 customer defined registers. Each register is programmable to accept pulses from two (five) of the following registers:

a) kWh Total Import b) kWh Total Export c) Q1 kvarh Import Lagging Energy d) Q2 kvarh Import Leading Energy e) Q3 kvarh Export Lagging Energy f) Q4 kvarh Export Leading Energy g) Input 1 h) Input 2 i) Input 3


Overview 13 ______________________________________________________________________

j) Input 4

Examples of their use are:

Register 1 Total kWh kWh Import + kWh Export (a + b)

Register 2 Total Import kvarh kvarh Lagging Import + kvarh Leading Import (c + d)

Register 3 Total kvarh kvarh Lagging Import + kvarh Leading Import + kvarh Lagging Export + kvarh Leading Export (c + d + e + f)

3.3 Time Keeping A fundamental part of the A1700 meter operation is its time keeping. To maintain accurate time it has its own clock with calendar capability. This clock is driven from a quartz crystal. There is an option to use the mains frequency as the basis of the clock. In the event of a power failure the clock will automatically resort to its crystal back up with the circuits supported by a stand-by battery.

In many countries there is a requirement to adjust the clock for daylight saving. This advances (in the Spring) or retards (in the Autumn) the clock at a preset date. The meter has the capability to perform this automatically by pre-programming these dates. The advance and retard can be one or two hours.

3.4 Data Logging Within the A1700 meter there is an option to store Demand Data for successive Integration Periods. The Demand Data can originate from any of the Primary Registers or Input Module inputs (if fitted). Primary Registers and module inputs can also be summated, for example:

Summate Input 1 kWh with Input 3 export kWh - (Input 1 + Input 3)

Summate kWh total import with Input 1 kWh - (kWh total import + Input 1)

The storage capacity is 450 days (with the option of 900 days) of data from one register at 30 minute demand intervals. In normal operation the information is extracted from the data logging store at regular intervals, e.g. daily or weekly.

The data storage can be allocated to a number of registers.

Example 1: It is possible to store 90 days of data (450 day version) when 5 primary registers are logged. For single register logging, only 225 days will be available if the integration period is 15 minutes.

Example 2: It is possible to store 180 days of data (900 day version) when 5 primary registers are logged. For single register logging, 450 days will be available if the integration period is 15 minutes.


4 CONFIGURATION, COMMUNICATION AND DATA COLLECTION

4.1 General The A1700 meter is configured by programming features from a pre-set list of options defined in the Power Master Unit. Programming is performed through the FLAG optical port or via an optional communications module.

The FLAG port can also be used to read from the meter for billing purposes. Programming and Reading are performed by Hand Held Units using an optical connector or directly, with the same connector, from a PC.

The RS232/RS485 communications module can be used for access to the meter over a telecommunications link from a remote point. The telecommunications link could be GSM Network, the Public Switched Telephone Network, a Radio Link or direct lines. The port, being a communications link, is of primary importance for down loading logged demand data. It can also be used for programming and reading in the same fashion as the optical port.

There are certain hardware features and security features that can be programmed and monitored through the communications ports. These include relay outputs, inputs, displays, alarms and clock time base. These add to the tariff options available to configure the application of the meter.

4.2 Support Systems The A1700 meter has a number of peripheral devices and software support systems, which together create the environment for communication, programming reading and displaying the data.

Figure 10 shows the total system capability.

GSM network A1700

Figure 10 Total System Capability


Overview 15 ______________________________________________________________________

4.2.1 Power Master Unit Software

Power Master Unit Software runs on an IBM compatible PC, allowing the A1700 meter (or PPM) to be programmed with tariff and hardware features. The operator is led through a menu driven sequence of data entries, which allows the operational features of the meter to be set up. The communications interface is either a direct connection from the PC through the optical port using a FLAG probe or through an intermediary device, namely a HHU or portable computer, which is carried to site. Alternatively the connection can be made over the selected communications medium using an appropriate modem. The most common way this is achieved is by an auto answer modem responding to calls over the PSTN from the central computer. The modem can be located under the terminal cover of the meter.

Power Master Unit Communications The Communications Server is invoked from the Power Master Unit and allows communication with the A1700 meter over local or remote communications links. There are two methods of establishing communications with a meter, by executing a Meter List or by using Quick Send via the Scheme Editor.

The Communications Server can be installed on a remote PC, allowing access over a network for a number of workstations. When networked the Communications Server must be open or communications with a meter will not be possible. The methods of communication and the network set-up are described in the Power Master Unit Manual (M120 001 6).

Meter List Scheduler The Meter List Scheduler is a Power Master Unit programming tool that allows a Meter List(s) set up in the Power Master Unit to be activated at a time scheduled by the software. This may be immediately (at the Start Time) or deferred (to the earliest opportunity on or after the Start Date).

4.2.2 CHIRPS When using the Hand Held Unit, a multi vendor software package, CHIRPS, (Common Hand Held Integrated Reading and Programming Systems) is invoked. It provides a common set of command and data structures, which allow a variety of meters from different manufacturers to operate with a variety of Hand Held Units.

The overall concept is shown in overleaf.


Figure 11 CHIRPS Overall Concept

To programme or read data from a particular manufacturer's meter or group of meters, the user employs the software specific to that manufacturer, to create the necessary meter schemes.

A meter scheme defines the reading and programming instructions to be applied to a meter or group of meters. Metering schemes are prepared by entering data into the Power Master Unit Software. This provides in simple menu driven format in a Windows environment, a series of data entries which define what data has to be read from the meter, e.g. number of tariffs, maximum demands etc. and data to be programmed into the meter e.g. tariff start and end times, seasons etc. Details are given in Chapter 6 (Software Support) of this manual. These instructions are formulated into CHIRPS files automatically. CHIRPS files, Reference and Sign-On files are generated and transferred to the Hand Held Unit.

Reference and instruction files are encrypted. The Hand Held Unit runs CHIRPS as an operating system and is thereby capable of interpreting these files to pass data to and from the meters. In the case of the PPM this transfer of data from P.C. to HHU uses an applications package referred to as OMS_TRAN.

There is a range of Hand Held Units available which run the CHIRPS environment. Details of the suppliers are available on request to Elster Metering Systems. Usually a user will have only one or two suppliers of Hand Held Units. The Hand Held Units interface to the meters on site using the FLAG probe. At any time it is possible to have data for a variety of meters held within the Hand Held Unit. The CHIRPS operating system will first identify the meter manufacturer, meter type and serial number during a sign on mode. After sign on, it will then refer to its database and select the appropriate instructions for that particular meter and transfer the data. The communications protocol between the HHU and the meter is FLAG IEC 62056 - 21 (formerly IEC 61107).

In most cases the transfer of information will be automatic with an indication at the end of the transfer that the operation is complete. It is possible to enter a manual entry mode where data can be entered directly from the keyboard e.g. resetting time and date, or view registers of interest. This will be in accordance with instructions set up on the P.C. however this option is not currently invoked in Power Master Unit Software.


Overview 17 ______________________________________________________________________

In the majority of operations the data transferred to the meter will be a request for meter readings. As a consequence data will be transferred back to the Hand Held Unit. This will be identified and stored in data files. The final transaction is to transfer meter data held in the Hand Held Unit to the P.C. for storage and display. This transfer takes place under the command of the Power Master Unit Software for each group of manufacturers meters. The information is stored as files in the P.C. in the Master Unit directories and is available for onward transfer to a mainframe computer for processing if the necessary file translation software is in place. In most cases it is simply viewed and checked for report purposes using the Master Unit Software.

The data structures within CHIRPS database are shown opposite.

The Hand Held Unit requests a sign on when interfaced to the meter. The meter responds with a response message. This entry level is held in a .SOD File. There is one .SOD File per manufacturer listing the types of meters available through CHIRPS.

Having gained entry the Hand Held Unit accesses the response and from this matches the meter database entry using the meter identification code. The meter database entries are held in the .REF File, which locates each meter loaded for programming and reading. Having located a meter database entry in the .REF File the .INS File is referenced. This determines the actions to be performed on a particular meter e.g. load new tariff, read data etc. These instructions are passed to the meter using the FLAG protocol.

The meter then responds with data or, if programme instructions have been sent, acknowledgement of acceptance. If data is being read it is stored in the .RES File. This stores sequential data as requested by the instruction database with each entry identified by the meter number. When load profile data is requested this data is stored in a .BUD File, (Bulk data).

On return to the P.C. the data held in the .RES File and .BUD File can be downloaded.

When assembling data in the Power Master Unit Software the instruction files and reference files are prepared automatically by setting up a meter list. These effectively give the reference address for the meters to be programmed and read. The details of programming and reading are prepared through entry data from the set-up screens detailed in the software manual. Instructions are passed to the meter using the FLAG protocol.



1 POWER AND ENERGY MEASUREMENT 2 PRINCIPLES OF ENERGY MEASUREMENT2.1 Energy Measurement Figure 1 3-Phase 4-Wire SystemFigure 2 3-Phase 4-Wire Vector Diagram2.2 Apparent Energy Measurement2.3 Reactive Energy Measurement 2.4 Four Quadrant Metering Figure 3 Four Quadrant Measurement2.5 Network Application2.5.1 3-Phase, 3-Wire Figure 4 3-Phase 3-Wire System2.5.2 3 Phase, 4 Wire Figure 5 3-Phase 4-Wire System2.5.3 2-Phases of 3-Phase, 4-WireFigure 6 2-Phases of a 3-Phase 4-Wire System2.5.4 1-Phase 3-Wire Figure 7 1-Phase 3-Wire System 2.5.5 2-Phase 3-Wire Figure 8 2-Phase 3-wire2.5.6 1-Phase 2-Wire Figure 9 1-phase 2-wire

3 TARIFF APPLICATIONS3.1 General 3.2 Tariff Features3.2.1 Billing Date3.2.2 Billing Period3.2.3 End of Billing Period3.2.4 Time of Use Registers 3.2.5 Switching Times 3.2.6 Seasons3.2.8 Integration Period3.2.9 Average Demand3.2.10 Maximum Demand3.2.11 Block Interval Demand3.2.12 Sliding Window Demand 3.2.13 Cumulative Registers3.2.14 Cumulative Maximum Demand3.2.15 Total kVAh3.2.16 Customer Defined Registers

3.3 Time Keeping3.4 Data Logging

4 CONFIGURATION, COMMUNICATION AND DATA COLLECTION4.1 General4.2 Support Systems Figure 10 Total System Capability 4.2.1 Power Master Unit Software4.2.2 CHIRPS

Figure 11 CHIRPS Overall Concept

Documents

2.Overview Section