Electricity Analytics- More than Customer Billing

Graeme McClure

Senior Protection & Control Engineer - Network Automation, SP AusNet

More to Smart Data then Remote Meter

Reading

Integration of Metering, GIS and SCADA Data

Benefits the Utility and indirectly Consumers

• Requires a knowledge of what the data represents

• How the data is obtained

• From where the data is sourced

•What values should be Expected

• Sources of distortion to the information obtained from data

Obtaining Information from Metering, Distribution and

Transmission Network Data Bases

The Value of Information derived from data can

be time Dependant

• A large number of beneficial outcomes can be obtained with

data which is hours / days or Months Old

• Major benefits can be obtained by having data available and

processed near real time

Applications with historical Data• Customer Billing

• Planning for Line and Transformer Loading

• Voltage Line Drop Compensation Fine Tuning

• Monitoring Service Cable condition (Safety)

• Customer Phase allocation

• Identifying locations for real time monitoring

• Strategic Asset Placement

• Identifying sites to investigate for non-technical losses

• Maximum Safe Load analysis of Protection

Applications with Near Real Time Data• Targeted Demand Response

• Closed Loop Line Voltage Regulation

• Customer Outage / Restoration Notification

• Micro Grid Stability

• Field Battery Discharge Test

• Phase Identification

• Meter Tampering

• Registered & Unregistered solar site identification

• Excessive protection operations

Applications with Near Real Time Data (cont.)

• SCADA triggers to auto extract fault recordings from relays

–Via engineering access (not SCADA)

• Flicker analysis

Advanced Metering Infrastructure (AMI)

• Interval Metering

• Under Voltage Alarm (unsolicited priority)

• Over Voltage Alarm (unsolicited priority)

• Tampering alarms

• Voltage

Customer Voltage Map (AMI Alarms)

• Telemetered Metering provides

indication of Under Voltage ,

Normal Voltage and Over Voltage

in Real Time

• Red Dots are Over Voltages

• Green Dots are Normal Voltage

• Can be used as feedback for IVVC

– exclude customers with solar as

control points

• What to do about customers who

are over voltage due to solar?

Load Balancing• Ideally equal real time loading on each phase

• Establish LV phasing connectivity for each transformer

• Summate AMI load data for each meter to create virtual transformer

load profile per phase

• Identify solar distribution across phase and affect on voltage drop

• Identify load to be moved to a different phase

• Establish correct phasing for HV line devices, ACRs etc.

• Identify lateral phases that can be moved to a different phase

• Identify single phase transformers that can be moved to different

phases

Load Balancing Important for Voltage Regulation

• The more uniform the load

distribution across phases, the

easier voltage regulation is to

achieve

Phase Identification

• All phases can be referenced real

time to a master phase identifier

• Use to correct phase reporting

for remote SCADA connected

devices

• Helps to balance load distribution

• Useful when commissioning new

devices

• Also use SCADA / AMI data

matching for faults and voltage

drop

Customer Phase allocation• Use supply outages and voltage drops to allocate individual

single phase customers to a particular phase.

• Phase out LV of an individual transformer

• Phase out HV line devices

• Phasing should be absolute so that customers on B phase on

one transformer can be compared to a customer on B phase

on another transformer for comparison of line loading

Transformer Load Planning

• Large load increases often experienced on Distribution Transformers

during Heat Waves

• Virtual Load Profile can be constructed by combining the load profiles

of those customers connected to the Transformer

• Virtual Load Profile run day after Heat Wave

• Used to identify those Transformers that Require Real time Monitoring

and Demand Response Capability

• SP – AusNet had approximately 300 Transformer Failures in 4 Days

during a Heat wave 3 years ago

Identifying sites to investigate for non-technical losses

• Phase measurement of a distribution transformer

• Phase assignment of customers

• Summations of customers on each phase

• Allowance for line loss

• Compare to actual measurement at the Transformer

• Flag areas for closer examination

• Also use line drop models based on Voltage at transformer

and each house

• Houses with measure values less the calculated value are

possibly consuming unmetered load

Meter Tampering

• Cover removal switches which are connected to alarms in

AMI

• Cross reference to works orders to see if legitimate

• Flag tamper alarms where no works orders for site

• Unauthorised disconnection of supply

–Removal of supply fuse to “work” on home

Maximum Safe Load analysis of Protection

• Checking load data from SCADA against Protection Settings

for field device

• Alarm when limits are encroached on

• For Over Current

• For Distance relay starter

–Plot position of mho for protection review

Line Loss Reduction

•For distribution companies no economic drivers at the

moment for line lose reduction.

•Under a Carbon Tax ?

•Regulatory Change ?

Field Battery Discharge Test• Small sealed lead acid batteries in the filed are a maintenance

issue for utilities

• Typical life 2 to 7 years

• Affected by Heat, charging conditions, Level of discharge

• Resistive load test periodically done on some

• Outage enables discharge testing to be done

–Know time until coms lost after supply loss

–Know expected hold up time for battery

–Flag batteries that didn’t keep communications going long enough / flat

Excessive protection operations

• Mostly an issue with ACR fast trips & trees

• ACR trips reclose on fast operation

• Tree contact isn’t lone enough for time delayed operation so protection

resets (40 seconds)

• Another fast trip occurs soon after

• etc.

• Can also be unravelling conductor strand

• Alarm if more than X operations in a time period Y (e.g. 6 in 3 hours)

– Dispatch crew to fix issue

– Indicate to temporarily suppress fast trip operation

SCADA triggers to auto extract fault recordings

from Relays• Via engineering access (not SCADA)

• Package and distribute for analysis

–Reduce to hours or min. way presently takes days if field staff dispatched

–Stored data often over written before it can be retrieved

–During a fault, not enough staff to do manually

–Data for difficult faults can aid analysis real time.

– Important for in depth post fault analysis

• Applicable for Transmission & Distribution

Voltage Regulation

Improve Environment for LV Embedded

Generation• LV Inverters should shut down when Voltage they need to

generate at is greater then 253 Volts

• Voltage to the zero current flow point held by dominant

generator (grid).

• Embedded generator needs to have voltage high enough to

allow for voltage drop from Inverter to the zero current flow

point

• Keep zero current flow point Voltage down to enable

maximum Voltage build on Inverters.

Voltage Profile of All Houses Polled

Enhanced Customer Safety

Detecting Failed Neutral Connection

Voltage Profile of All Houses Polled

Voltage Profile of Individual House

Closed Loop Voltage Regulation

Why Closed Loop Voltage Regulation?

• Embedded feeder Generation

–Domestic Solar

–Small Generators (Base load 300kVA to 8 MVA)

– Intermittent Generators (Wind, peak micro Generation)

• Voltage Compliance

• Demand Reduction during Peak Loading time

–Set before Load Shedding

–Differ Capacity Upgrades on individual Feeders

Closed Loop Voltage Regulation

• Real Time Voltage (LV) Monitored in the Field

• Used to control the Tap Position of Zone Substation LTC

• Also used to control Tap Position of Line Regulators

• Control Switching of field capacitor banks

• Objective to reduce the Voltage spread at individual supply

Points

• Makes driving the Voltage at supply points lower possible

Customer Outage / Restoration

Notification

Outage Management

• Important to Know Both Loss and Restoration of Supply

– Many examples of when an individual Customers Supply Fuse Operates at the same

time as Major Line Protection Device

• Call Out Crew fixes Main issue and assumes that everybody is back on

• Secondary Call Out Hours Later to Restore Supply to Individual Customers

– Credit in Network Performance for Partial Restorations

• Integration of SCADA Data and Metering Information in Real Time

• Important that it is Loss of Supply NOT Loss of Communications

• Used to Audit SAIDI, SAIFI & MAIFI

Micro Grid Stability

Real Time Data accessible locally

• Historical Metering Data used to select real time Monitoring

Locations

• SCADA signals communicating locally to control generation,

Storage & Switching

• SCADA requests to Metering system for Demand Response

so as to NOT overload Micro Grid Capability

–Load Shed Water Heating

–Demand Restriction of Customers?

–Contracted Manageable Loads

QUESTIONS ?

Issues That Need to Be Considered When

Designing Smart Data Applications

Missing Data

• Not all data sources are present for the historical point of

time you are mining for

• Equipment can go offline

• Disruption to data with equipment failure and change over

Flat Lining

• Transducers can lockup

• Maintaining a variable such as ambient air temperature at a

constant value is an indication of flat lining

• Affects variables such as

–Temperature

–Currents

–Voltages

–Complex analogue variables

Order of Magnitude

• Simple Order of Magnitude storage of values can cause

issues. Especially if they come form different transducer

types. i.e. CB feeder relay and down line switch.

Range Control

• Range control can often clip analog variables causing them to flat line at a magnitude higher or lower then expected.

• Example of a variable for SWER line Voltage. Record indicated a constant 8 kV. Line voltage should have been nominally 12.7kV. Two issues;–Value less then expected.

–Value flat lined, would expect some small fluctuation. Note when line was off this value also went to Zero.

– Initially Suspected incorrect variable mapped

Signed Data

• Signing of data can cause issues when looking at data from

different sources about the same physical quantity.

–Mostly when analysis is done of binary variables

Events Generated during Test & Commissioning

• Operation number for field devices can look higher than

actual field performance

• Distorts network reliability analysis unless filtered out.

• Many IEDs cannot exclude testing from their wear and life

indicators

• Desirable to have flags to indicate data being generated by

test and commissioning

Variations Due to Network Switching

• The operation of the network can affect what loads are

connected to a particular part of the electricity network at any

point in time

• Apparent Load increase could be due to extra line segments

being switched onto the end of the line.

– Issue when looking for maximum line loads

Phase Rotation

• Line construction can affect the mechanical position of

electrical phases

• Field transducers often assume phases allocated to a

mechanical position. i.e. B phase is in the centre. A phase is

on the left and c phase on the right.

–Affected by which side of the pole a transducer is located on

–Phase rotations associated with power lines Teeing off around corners

• Makes line segment loading calculations problematic

Field Time and SCADA time

• Because of communications delays often desirable to

process events based on field time rather the time stamp

associated with data being received.

• Some systems don’t report field time correctly

• Important to note time source when reconstructing events

record

Time Synchronisation and Drift

•When considering the sequence of data from different

transducers consideration should be made for the degree to

which field time can be compared

–Are all the times synchronised to the same time ?

– Is their an offset in some IEDs ?

–To what accuracy ?

–What is the clock drift of the IED ?

–What is the accuracy to the synchronisation method ?

Daylight Savings

• Sometime daylight savings adjustments is made to records

– Is it a correction on the display only?

–What is the base time of the raw data?

–Are the transducers affected by daylight savings? i.e. new smart meter

clocks.

–Does the real world change with daylight saving, however the data locked

to UTC for example.

Accuracy and linearity of Field Transducers

• Often variations are seen because the field devices are not

linear over the complete range being monitored.

–Notably current Transducers recording fault levels

–Did the transducer have sufficient time to accurately record field value

e.g. high magnitude fault currents

–What is the accuracy to the field transducers?