Pqn Pq Management

8/12/2019 Pqn Pq Management

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What are the aspects ofWhat are the aspects of

Power QualityPower Quality

Management ?Management ?

Overview

An appropriate regulatory framework

Extensive PQ and interruption monitoring programs

National PQ standards

Customer PQ contracts

Customer PQ forums

Transmission/Distribution PQ contracts

Long-term sustainability measures

Short-term business targets

Network technical solutions Behind-the-meter solutions


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How does a power qualityHow does a power quality

database form a businessdatabase form a business

tool ?tool ?

Monitoring Program

Since 1998 most TX/DX (114) supply points (mainly

132kV, and 88kV) are permanently monitored.

The following 10-minute parameters for all three

phases are stored on a national Database (together

with data from about 400 Distribution monitors):

Voltage magnitude

Unbalance

Harmonics (3, 5, 7,11, and 13th harmonics)

THD Dips on the individual phases are also stored for all

Tx/Dx sites. These are matched to faults on the

network.


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Eskom Statistics

Since 1998

Registered users (>200)

10 min values (> 1 billion)

Dips (> 500,000)

Monitoring Program Instruments downloaded daily or interrogated

Various security levels (administration, users)

Audit

Instrument connectivity / tracking

Daily summation of data

Link events with causes (e.g. line faults)

Specific contractual limits flagged

Web access to customers


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Central Server/Environment

DataLoaders

LoaderManager

Oracle

DataStore

Oracle

Data

Warehouse

Summator

DataView

Area A / Area B / ...

Data Retrieval/

Placement

Eskom Wide

Reports

DRPArchiving

SecurityAuditing

Db link

Other

Systems InterfaceManager

LimitManager

ODBC

Data

Manager

DataConvertors

Reports

PQ Database

POWER QUALITY SHORT COURSEPOWER QUALITY SHORT COURSEVoltage Dips: Utility ManagementVoltage Dips: Utility Management


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Business Features

Security

Audit

Integration

Instrument connectivity / tracking

Daily summation

Link events with causes

Specific contractual limits flagged

Customer PQ Information

Web access to closest monitored sites (key customers)


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What is an OperationalWhat is an Operational

Sustainability Index ?Sustainability Index ?

Sustainability index

Aims:

Assurance that plant is not abused for

the purpose of short-term benefits

Ensure companys long-term success

as a viable business

Provide adequate warning of negative

trends


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Sustainability Index

PRINCIPLES BEHIND ALARM ANDSTANDARD SETTINGPlanning figure

Alarm

Standard

Target

Ceiling

B K-I E T CImprovement direction

F

Increasing score loss

200:1 (99.5%)

5:1 (80%)

1:1 (50%)

20:1 (95%)

Impossible Best Ever Benchmarked Stretch Expected Slack

Target Appraisal

Aim: To provide executive management with a

view on the targets set by the individual line

groups

50%20%


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Sustainability IndexMeasure Weight Jun-03 Jul-03 YEP

Overall Score90.97 90.97 90.70

Generation

Energy Availability Factor ( Availabilty) 6.10 Alarm Alarm Alarm

Unplanned Capability Loss Factor (Reliability) 6.10 Score= 66% S core= 66% S core= 66%

Unplanned Automatic Grid Separations (Reliability) 6.10 OK OK OK

Long Term Plant Health (Health) 6.10 OK OK OK

Nuclear Performance (Health) 6.10 Alarm Alarm Alarm

Low Frequency Incidents (Generation Contribution) 2.75 OK OK OK

Transmission

Transmission Availability 6.10 Sc or e= 89 % Sc ore = 8 9% Sc or e= 89 %

Transmission Reliability 9.76 OK OK OK

Transmission Disturbance 2.89 OK OK OK

Transmission Waveform 1.73 OK OK OK

Transmission Customer 2.25 Alarm OK Alarm

Distribution

Distribution Reliability 2.11 Alarm Alarm OK

Distribution Disturbance 4.40 OK OK Alarm

Distribution Waveform 3.60 OK OK OK

Distribution Customer 15.63 Sc or e= 83 % Sc ore = 8 3% Sc or e= 82 %

Common

NER Compliance 6.10 Alarm Alarm Alarm

Conventional Safety 6.10 Sc or e= 40 % Sc ore = 4 0% Sc or e= 40 %

Environmental 6.10 Alarm OK OK

Experience: Voltage Magnitude In 2000 relays on PQ instruments at T&D interfaces

used to send alarms based on 10-minute values to

National Control

Together with automatic tap changer optimisation

resulted in a dramatic improvement in performance

Upper limit

Lower limit

00h00

.

X (alarm on)

Y (alarm off)

Time

00h10

00h20

00h30

00h40

Voltage


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Technical InterventionsPercentage of sites exceeding voltage magnitude

objectives at T&D interface points

17.4

14.3

7.15.4

3.63.6

21.4 21.4

18.8 19.7

54

1

6

11

16

21

26

Feb-00

Mar-00Ap

r-00

May-0

0

Jun-00Jul-00Au

g-00Se

p-00Oc

t-00No

v-00De

c-00Jan-01

2000/2001

%

12 MMI

SI Standard

SI Alarm

Sustainability IndexTechnical Audit Department

Transmission - Quality of SupplyQOS - Voltage Regulation

15.9

17

6.2

4.5 4.5

16.2

4

5

0

5

10

15

20

1997 1998 1999 2000 2001 2002 2003 2004 2005

%S

ites>NER/SALimit

Actuals Standard Alarm NER, 1999 - 2002 TBP congruant 2003 TBP

2002 Actual - Aug YEP

Pre-2001 discounting not applied.

Month by month information based on new rules not available.


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Customer rights

Contact within 2 working days If measurements required, free for first 2 weeks

If not conclusive, IR process (e.g. problemgone)

If solution is practical and economic, Eskom willput in place actions to resolve

Report within 6 weeks, otherwise regularfeedback

NCR process to NER

Provision of investigation number

Managed contract: install a meter at customercost, and a monthly cost

What are typicalWhat are typical

equipment failureequipment failure

statistics for MV and LVstatistics for MV and LV

customers ?customers ?


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MV Power Quality and Reliability

PICPIC

CC-MaximoCC-Maximo

OIDs/NEPSOIDs/NEPS

MaximoMaximo

12 months

13,000 claims /

complaints

call centre

rural/urban

connection

detail (text)

Direct ContactDirect Contact


0

50

100

150

200

250

300

Number

Bellville

Bloem

fontein

Mkondeni

Johannesburg

No

rthEast

N

orthern

S

outhern

TOTAL CLAIMS LOGGED ON PIC

1 Jul 2002 - 30 Jun 2003SUPPLY-RELATED CLAIMS LOGGED ON PIC

0

5

10

15

20

25

30

35

40

45

Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun

2002/2003

Number

Bellville

Bloemfontein

Mkondeni

Johannesburg

NorthEast

Northern

Southern


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0

20

40

60

80

100

120

140

160

180

Number

TV's

Fridges

Computers

Pumps

Radio's

Motors

CD/DVD's

HIFI's

Microwaves

VCR's

Kettles

Irons

Faxmachines

Lightbulbs

LOSSES REGISTERED ON PIC: JULY 2002-JUNE 2003

(Excluding faxes and letters referred to in PIC)

Power Quality ContractsPower Quality Contracts


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Contractual PQ Relationships

EskomTransmission

Eskom

Customers

T&D

Interfaces

Formal Internal

T&D agreements

Eskom

Distribution

InternationalConnections

Re-distributors

Re-distributor

Customers

Customer

Interfaces

Formal Supply

Contracts

Contracts with re-distributors supplied from the transmission system

are developed and managed by Eskom Distribution.

Contractual relationships

T&D agreements at internal supply points and supply

contracts at bulk delivery points are based on

The requirements of NRS-048

Contracts with customers supplied at HV or EHV

Historical performance data


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Customer Contracts

Eskom PQ performance defined Customer disturbance limits

Based on NRS 048:2

Quality Options

Standard

Managed

(Network Specific)

Premium power

Standard Contract:

This will make reference to NRS-048, i.e.that Eskom as a company will meet NERrequirements

This includes the 5% allowable exceedances

This is predominantly for customers who willnot be concerned with voltage dips

No cost implications to the customer

Power Quality Contract Options


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Power Quality Service Contract:

Eskom will provide:

historic dip performance

on-going dip performance information

location of faults

causes of faults where known

any action plans to improve the dipperformance

The customer could pay for this service andthe meter

This information will be published on thewebsite


Network Performance Contract:

This includes the Power Quality ServiceContract option

Contracted limits based on valid dipperformance data

At least 5 years of data with an instrumentavailability of at least 300 days per year

This contract is usually only entered into aftera period that the Power Quality ServiceContract has been in place



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Premium Power Contract:

Eskom will provide a guaranteed level ofquality that meets the customers specificneeds

The full cost of the solution, maintenancecosts, service costs, and risk costs will becharged to the customer

This contract can be entered into at anytime with a customer


How do internationalHow do international

utilities view PQutilities view PQ

contracts ?contracts ?


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Contracting

POWER QUALITY CONTRACTS

Degree of Interest in Im plementat ion(average non-exclus ive weight ing)

- Standard

- Netw ork Specif ic

- Premium Power

LOW MEDIUM HIGH

Survey: 27 Utilities

Formal program: active implementation

Informal program: ad-hoc

implementation

Under consideration: presently

considering implementation

No program: no program and no

intention to implement such a program


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0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

Percentage of

Utilities

Contracts Custom Power

UTILITY POWER QUALITY SERVICES

Formal Program

Informal Program

Under Consideration

No


PQ contracting: impacted by regulatory

conditions, standards for benchmarking,

and litigation concerns in the US

Custom power programs: in all most all

cases the customer is required to pay for

the solutions


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CASE STUDY:CASE STUDY:

EDF Quality PlanEDF Quality Plan

Case Study: EDF Contracts

Contracts put in place first with 6000 MV customers,

and then all MV customers (>250 kW).

Reflected the improvement in the guaranteed

individual customer interruption performance

statistics over a 5-year improvement plan.

Called the Emeraulde Contract.

Reflects the utilitys commitment to power quality

and applies the principle of offering financial

compensation based on overall damages incurred if

one of the agreed limits is exceeded.

These limits determined at national level.


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Case Study: EDF ContractsCustomer

categories

Interruptions Area

categories

No.

Customers supply All interruptions 1 36

with two feeders > 1 s 2 13

and automatic 3 6

change over 4 4

16

Sustained interruptions 2 3

Other customers > 3 min 3 3

4 2

Momentary interruptions1

30

1s < duration


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How are limits for largeHow are limits for large

customers negotiated ?customers negotiated ?

STAGE 2 Specificcontractual limits

Load emission evaluatedw.r.t. total emission fromother loads

(standard procedure)

exceedsStage 1

STAGE 3 Specificcontractual limitsand specifiedconditions

Load emission evaluatedw.r.t. total emission from

other loads and specificlocal conditions

(special study)

exceedsStage 2

Design mitigationstrategy to reduce loademission or networksensitivity

exceedsStage 3

Standardcontractualclauses

Load too small toimpact PCC levels

START

(standard tables)STAGE 1

Defining plant emission levels


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Voltage QualityVoltage Quality

ALLOCATIONALLOCATION ((LIMITLIMIT -- BACKGROUNDBACKGROUND).).MVAMVA11

MVAMVAii

}

}}

STAGE 2 allocation

Concession based on technical

motivation (no additional risk)

Concession with risk transferred

to customerSTAGE 3

STAGE 2

Contractual risk management


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Contractual risk managementContractual risk management

Examples of technically justified concessions: large non-flicker-generating load at PCC

high HV/LV attenuation ratios

Examples of risk transferred

future emission-producing loads

generator availability / nuclear station future

long-term equipment outages

customer complaints (if above standard)

concessions by the NER to temporarily

allow higher levels

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Pqn Pq Management