Prepared by, DR. KOK BOON CHING 2012@JEK/FKEE 1 BEX 42803 – UTILISATION OF ELECTRICAL ENERGY

1

Prepared by,

DR. KOK BOON CHING 2012@JEK/FKEE

BEX 42803 – UTILISATION OF ELECTRICAL ENERGY

CHAPTER 1DISTRIBUTION SYSTEMS AND TARIFFS

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Outlines

• Introduction• Electricity Generation Scenario in

Malaysia• Electric Supply System• HV Distribution Networks• LV Distribution Networks• Hardware for Distribution Systems• Load Characteristics and Tariffs Rate

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Introduction

• Energy is needed in many areas of human endeavor such as: moving people and goods around -

TRANSPORT producing and processing of food -

AGRICULTURE manufacturing of useful materials

and artifacts - INDUSTRY Powering communication gadgets

and equipment, and going about other commercial activities - COMMERCE

maintaining physical comfort and convenience in our homes - HOUSEHOLDS

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• Transportation is the movement of people and goods from one place to another.

• Transportation depends on continuous supply of energy.

• Automobiles are powered by gasoline (petrol), aeroplanes by jet fuel (kerosene), and trucks, trains, and ships by diesel oil.

• Conveyers, cranes, robots and pipelines use motors and pumps, which are powered by electricity.

Introduction - TRANSPORT

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• Agro-industries and processing of agricultural products require energy.

• Mechanical implements powered by fuel or electricity are immensely more efficient and productive than humans and animals.

• In developed countries, a major portion of electricity used in agriculture powers irrigation pumps.

• The energy requirements in agriculture are mainly met using solar energy, fossil fuels (oil, coal and natural gas), fuel wood and electricity.

Introduction - AGRICULTURE

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Introduction - INDUSTRY

• Most of the energy used in industry is used by the machines and processes, which make the products of industry.

• Industrial energy-consuming systems include boiler and other fired systems (furnace, kilns, incinerators, dryers), compressed air system, electric motors (for fans, blowers, pumps, conveyers, etc.) and lighting system.

• Energy is also used to heat or cool the buildings and to provide hot water and other facilities for workers.

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Introduction - COMMERCE

• Highly sophisticated communication systems both for the supply of goods and services, and the maintenance of organisational cohesion requires a ready supply of suitable energy.

• Energy in commerce is basically use for information processing, ACMV, and lighting.

• Electrical energy is the most common form of energy used and supplemented by chemical energy from batteries (renewable energy system).

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Introduction - HOUSEHOLD

• Energy is required in households for space heating or cooling, water heating, cooking, lighting, ironing, and power appliances like fridge, washing machines, sound systems, TV, hair dryers, shavers, clocks, blenders, toasters, vacuum cleaners, sewing machines, etc.

• The energy may come from direct heating from the sun, electricity, burning of fossil fuels or fuel wood.

9 Inst

alle

d C

ap

aci

ty b

y F

uel Ty

pe

(20

10

)

Generation Mix Profile in Malaysia

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Generation Mix Profile in Malaysia

Inst

alle

d C

ap

aci

ty b

y P

ow

er

Pro

du

cers

(2

01

0)

11

Number of Consumers by Sector

Mala

ysi

a (

20

10

)

12

SALES OF ELECTRICITY (Peninsular)

13 Maj

or P

ower

Sta

tion

in P

enin

sula

r M

alay

sia

(201

0)

14

Some of Thermal Power Plants in Peninsular Malaysia

LEGENDHydro

Thermal

LEGENDHydro

Thermal

Note:GT - Open Cycle Gas TurbineCC - Combined CycleCSP - Conventional ThermalC/G/O - Triple Fuel Coal, Oil & GasDist - Distillate

SOUTH CHINA SEASTRAITS OF

MELAKA

N Teluk Ewa (68 MW)GT 2 x 34 MW Dist

PRAI (360 MW)CSP 3x120 MW Fuel Oil

GELUGOR CC 1 x 330 MW GasSERDANG (625 MW)GT 3x135 MW GasGT 2x110 MW Gas

CONNAUGHT BRIDGE (832 MW)

GT 4x 130 MW GasCC 1x 312 MW Gas

PORT DICKSON (360 MW)CSP 3x120 MW Gas/Oil

PASIR GUDANG (729MW)CSP 2x120 MW Oil/Gas

CC 1x269 MW GasGT² 2x110 MW Gas

PAKA (1,139 MW) CC 3x290 MW GasCC 1x269 MW Gas

KEV (2,420 MW)CSP 2x500 MW Coal/G/OCSP 2x300 MW Coal/G/OCSP 2x300 MW Gas/Oil

GT² 2x110 MW Gas

MANJUNG (2100 MW)3 x 700 MW CoalTANJUNG BIN (2100 MW)3 x 700 MW Coal

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Some of Hydro Power Plants in Peninsular Malaysia

Note:GT - Open Cycle Gas TurbineCC - Combined CycleCSP - Conventional ThermalC/G/O - Triple Fuel Coal, Oil & GasDist - Distillate

SOUTH CHINA SEASTRAITS OF

MELAKA

N

LEGENDHydro

Thermal

LEGENDHydro

Thermal

Bersia3 x 24MWKenering3 x 40MW

Chenderoh3 x 10.7 MW1 x 8.4 MW

Cameron Highland261.9 MW

Sg.Piah2 x 7.3 MW2 x 27 MW

Pergau4 x 150MW

Kenyir4 x 100MWTemengor4 x 87 MW

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Maximum Demand and Installed Generation Capacity

Pen

insu

lar

Mal

aysi

a (2

010)

(Source: Electricity Supply Industry in Malaysia: Performance and Statistical Information, Suruhanjaya Tenaga, 2010)

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Sab

ah (

2010

)


18


Sar

awak

(20

10)


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Electricity Forecast (2007 – 2011)

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TN

B G

RID

SY

ST

EM

201

0

21

TN

B G

rid S

yste

m (

2006

)

22

MA

JOR

PO

WE

R S

TAT

ION

AN

D G

RID

S

YS

TE

M I

N S

AR

AW

AK

(20

10)

23

MA

JOR

PO

WE

R S

TAT

ION

AN

D G

RID

S

YS

TE

M I

N S

AB

AH

(20

10)

24

Pro

spec

tive

AS

EA

N P

ower

Grid

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Electrical Supply Systems

• Medium/High Voltage (HV) Overhead transmission lines (500 kV,

275 kV). Underground cables (132 kV, 66 kV, 33

kV, 22 kV, 11 kV, 6.6 kV). For large scale industry customers.

• Low Voltage (LV) Voltage level below 1 kV (240 V and 415

V). For residential, commercial, and small

industry applications.

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Definition of Voltage Levels

1 kV 50 kV

Low Voltag

e

Medium

Voltage

High Voltag

e

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Low Voltage (LV System)

• Single-phase, 2-wire, 240 V, up to 12 kVA maximum demand

• Three-phase, 4-wire, 415 V, up to 45 kVA maximum demand

• Three-phase, 4-wire, C.T. metered, 415 V, up to 1000 kVA maximum demand

Citation: TNB Electricity Supply Application Handbook, 2nd Edition, March 2007

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Medium and High Voltage (MV & HV)• Three-phase, 3-wire, 11 kV for load

of 1000 kVA maximum demand and above

• Three-phase, 3-wire, 22 kV or 33 kV for load of 5000 kVA maximum demand and above

• Three-phase, 3-wire, 66 kV, 132 kV and 275 kV for exceptionally large load of above 25 MVA maximum demandCitation: TNB Electricity Supply Application Handbook, 2nd Edition, March 2007

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Steady-state Supply Voltage Performance

Voltage Level % variation

415 V and 240 V -10% & +5%

6.6 kV, 11 kV, 22 kV, 33 kV 5%

132 kV and 275 kV -5% & +10%

Under normal conditions

Voltage Level % variation

415 V and 240 V 10%

6.6 kV, 11 kV, 22 kV, 33 kV +10% & -10%

132 kV and 275 kV 10%

Under contingency conditions

Citation: TNB Electricity Supply Application Handbook, 2nd Edition, March 2007

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Security Levels for Distribution Systems

• For voltage levels of 6.6 kV, 11 kV, 22 kV and 33 kV – the average supply restoration is less than 4 hours.

• For supplies at 240 V and 415 V – the restoration period may vary beyond 4 hours depending on the type of network fault.Citation: TNB Electricity Supply Application Handbook, 2nd Edition, March 2007

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Overview of Electricity Supply Systems

Str

uct

ure

of

the P

ow

er

Syst

em

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High Voltage Electrical Supply

A. Main Transmission Line Network System Connecting the electrical supply source

from electrical generation stations to the main distribution network system at certain large areas like states, districts and big towns.

The main transmission line networks are liked to each other to form the “National Grid System”.

The method used in the transmission line network is the 3ø, 3 lines (R-Y-B) system through main overhead line tower.

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B. Primary Distribution Network System It receives electrical supply from main

transmission line network system. It is located at few selected locations in

a state. The electrical power is delivered to the

users through 4 distribution levels.

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American Versus European System

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First Level (1) – Transmission Main Intake (TMI) or Pencawang Masuk Utama (PMU). Interconnection point of 132kV or 275kV to

the distribution network.The standard transmission capacity and voltage transformation provided at the PMU are as follows:-- 132/33kV, 2 x 90 MVA- 132 /22kV, 2 x 60 MVA- 132 /11 kV, 2 x 30 MVA

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Second Level (2) – Main Distribution Sub-station (MDS) or Pencawang Pembahagian Utama (PPU).

Main Distribution Sub-station is normally applicable to 33kV for interconnecting 33kV networks with 11 kV networks.

It provides capacity injection into 11 kV network through a standardized transformation of 33/11 kV.

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Third Level (3) – Main Switching Station (MSS) or Stesyen Suis Utama (SSU). SSU at 33kV, 22kV and 11 kV are

established to serve the following function:

1. To supply a dedicated bulk consumer ( 33kV, 22kV, 11 kV)

2. To provide bulk capacity injection or transfer from a PMU/PPU to a load center for further localized distribution.

http://1.bp.blogspot.com/_7-atFjouYU8/SzGKQpHT1JI/AAAAAAAAACI/Q7t44I-D1bo/s1600-h/ssu+seagate.jpg

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Fourth Level (4) – Distribution Substation (DS) or Pencawang Elektrik (PE). Distribution sub-stations are capacity

injection points from 11 kV, 22kV and sometimes 33kV systems to the low voltage network (415V, 240V).

Typical capacity ratings are 1000kVA, 750kVA, 500kVA and 300kVA.

http://2.bp.blogspot.com/_7-atFjouYU8/SzGLFIJ2h5I/AAAAAAAAACQ/oov3E-RBliQ/s1600-h/IMG_0855.JPG

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Under ground cables are used in the delivery system from level 1 – 4.Types : 3C x 300 mm sq/ 3C240 mm sq/

3C185 mm sq, XLPE (cross-linked Polyethylene), Aluminum.

Block diagram:

MTL TMI MDS MSS

DS

DS

132kV/33 kV/11kV

33 kV/22 kV

33kV/22 kV/11 kV

…

11kV/415 V(LV)

1 2 3

33kV/11kV 22 kV/11kV

4

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C. Secondary Distribution Network System Begins whenever the High Voltage

electrical supply (11KV) received at DS is converted to Low Voltage electrical supply (415V).

Method used is the 4 lines (R-Y-B-N) through step-down transformer.

The number of DS is depends on the total load demands (VA) requested by the user.

Type of DS : Single Chamber (200 A) and Double Chambers (600 A).

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Number of chamber indicating the number of transformers needed. (2 chambers type can be recognised with 2 doors of the size of 2400 mm wide X 3000 mm high)

Type of transformer : Oil Immersed Type, cheap but low efficiency

(for small users).Cast Resin - Dry, more expensive but higher

efficiency (larger customers). Nominal Volt-Ampere capacity of the

transformer: 300 kVA, 500 kVA, 750 kVA, and 1000 kVA.

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What are inside the DS?1) Switch gear2) Transformer3) Low Voltage Distribution Board

The 415V supply will then connected to the kWh metering system (user side) through LV underground cables.

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Layout of an DS (Single Chamber):

LV Board

Switchgear Room

Transformer Room

Outgoing Points

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Single Chamber DS

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Double Chamber DS

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D. Types of Electrical Supply Users: HV – Higher institutions, shopping

complexes, large factories (owned the MDS, MSS, DS).

LV – Domestic users, shop lots, public buildings.

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Low Voltage Electrical Supply

• Types: 3ø, 4 wires + E – 415V 1ø, 2 wires + E – 240V

• Types of LV electrical installation: Small Industry Buildings. Small Commercial Building (shop, office,

restaurant). Small Residential Building (Condo, Terrace,

Apartment). Small Public Building (wet market, bus station,

….) Public Utilities (Street lights, traffic lights,…..)

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• Main components in a LV electrical supply distribution system (building): kWh meter TNB Main Switch Board (MSB) Sub Switch Board (SSB) Distribution Board (DB)

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• Example of residential connection:

DS M Loads

TNB Consumers

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• Example of industry connection:

DSMSS

FACTORY

MSB

HT Switch Room

HT Meter Room

HT Switch Room

User’s Transformer Room

Main Switch Board

SSB

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Main Switchboard (MSB)

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Sub Switchboard (SSB)

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• Example: Double-storey House Lighting Power

DB2

Lighting Power

DB1

M

1st Floor

Ground Floor

Incoming TNB

kWH meter TNB

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• Example: Terrace house installationTerrace House

TH 1 TH 2 TH 3 TH 4

Service Cable

kWHMeter

Road

MM M M

Tap- off Unit

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Economic Aspects

• Utility company must plans for the electricity demand in advance as requested by its consumers.

• Common terms used: Connected load Maximum demand Demand factor Average demand Load factor Diversity factor

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Economic Aspects

• Connected Load – sum of the rated maximum values of all loads used by consumer. It may be expressed in watts, kW, A, hp, kVA etc.

• Maximum Demand – highest or peak demand for a specified time (might be in hour, day, month, or year).

• Demand Factor (DF)load Connected

demand Actual DF

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Economic Aspects

• Average Demand – Sum of the total demand (in kWh) divided by the demand period (hr).

• Load Factor (LF) - The ratio of the average load over the peak load. LF is always ≤ 1.

(hr) period Demand demand Maximum

(kWh) load Average LF

or

demand Maximum

kW)(in demand Average LF

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Economic Aspects

• Diversity Factor (Div F) - The ratio of the sum of the individual maximum demands in a distribution system to the maximum demand of the whole distribution system.

• For consumer – Div. F < 1.0• For generation supplier – Div. F > 1.0

Demand Max. Group

Demand Max. Ind. F Div

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Example 1 – Economic Aspects

A load rises from zero to 10 kW instantaneously and stays constant for 1 minute, then rises to 20 kW and remains constant for 1 minute, continues at this rate of rise until it reaches a maximum value of 50 kW for 1 minute, then instantly falls to zero for 1 minute, after which it again rises in 10 kW steps at 1 minute intervals to a maximum of 50 kW and returns to zero for 1 minute. If the load continues to vary in these steps:i. What is the average demand over the first 15

minutes?ii. Over the second 15 minutes?iii. Over the 30 minutes demand interval?

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Solution:

10

20

30

40

50

kW

15 minutes

Time (minute)

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Solution (Cont.): (i) Total demand = (10 kW x 3 + 20 kW x 3 + 30 kW x 3 + 40 kW x 2 + 50 kW x 2) = 360 kW Average demand over 15 minutes = 360 kW/15 minutes = 24 kW.

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Solution (Cont.):(ii) Total demand for the second 15 minutes= 390 kWAverage demand = 390 kW/15 minutes = 26 kW(iii) Total demand over 30 minutes= 360 kW + 390 kW = 750 kWAverage demand = 750 kW/30 minutes = 25 kW

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A factory consumes 425,200 kVAh in a yearwith the yearly average power factor, 0.86. Ifthe half-an-hour demand was 120 kW, find,i. The average load demandii. Annual load factoriii. If the factory decided to increase the

electricity usage to 450,000 kWh and the load factor to 65%, what will be the maximum demand?

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Solution:(i) Average load demand= (425,200 x 0.86) kWh/ (365 x 24) hr= 41.74 kW.(ii) Load factor = 41.74 kW/ 120 kW =

35%.(iii) Maximum demand= 450,000 kWh/ (8,760 x 0.65) =

79.03 kW.

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A group of Parit Raja consumers has a total annual individual maximum demand of 132 kVA supplied from a single phase distributiontransformer. If the average diversity

factorbetween the group of consumers is

2.8,determine the nearest standard size of

thedistribution transformer that serving

theconsumers.

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Solution:The size of the transformer is determinedaccording to the maximum demand of the whole group.Group Maximum demand,= Annual individual maximum demand/ DF= 132 kVA/ 2.8= 47.14 kVA. Nearest standard size = 50 kVA.

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Tariffs

• The rate of charging for electrical energy supplied by the utility company to its consumer.

• Tariff charge is depends on various factors: Type of consumer (industrial,

commercial, or domestic) Type of service (lighting, heating, etc) Total fixed running annual charges

of the utility company Facility for calculating the bill

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Tariffs

• Definition of electricity tariff:

• 3 types of tariffs:i. Residentialii. Commercialiii. Industrial

[kWh]consumer the tosuppliedenergy Total

[RM] running) (fixed charges actual Total Tariff

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TNB Tariffs

• Refer to “ TNB Tariffs Book” (updated 2011).• Power Factor Tariff (Low Power Factor Penalty):

Below 0.85 and up to 0.75 lagging, 1.5% of the bill for that month for each one-hundredth (0.01).

Below 0.75 lagging, A supplementary charge of 3% of the bill for that month for each one-hundredth (0.01).

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Example 4 – Power Factor Tariff

A medium voltage industrial consumer having

the following data for its monthly electricity bill:• Total electricity consumption in kWh

- 160,000 units• The reactive power consumption in kVArh

- 120,000 units• The monthly load factor - 68%• For each kilowatt of maximum demand per

month

= RM 25.30/ kW• For all kWh = 28.8 cents/ kWh

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i. Determine the monthly maximum demand for this consumer. [take 30 days/month]

ii. What is the total monthly bill charge for this consumer?

iii. Recalculate the total monthly bill charge if the reactive power consumption is increased to 150,000 units.

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Solution:

(i) Monthly max. demand

= 160,000 kWh/(0.68)(30 x 24) = 326.80 kW.

(ii) Monthly bill without PF consideration,

= 326.80 kW x RM 25.30 + 160,000 kWh x RM 0.288

= RM 54,348.04

PF = cos (tan-1 120,000/160,000) = 0.8

Poor PF charge = 1.5% x (0.85 - 0.8) x 100 x RM54,348.04

= RM 4,076.10

Total monthly bill charge = RM 58,424.14

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Solution:

(iii) Monthly bill without PF consideration,

= 326.80 kW x RM 25.30 + 160,000 kWh x RM 0.288

= RM 54,348.04

PF = cos (tan-1 150,000/160,000) = 0.73

Poor PF charge = [1.5% x (0.85 - 0.75) + 3.0% x (0.75 - 0.73)] x 100 x RM54,348.04 = RM 11,413.09

Total monthly bill charge = RM 65,761.13

Documents

Prepared by, DR. KOK BOON CHING 2012@JEK/FKEE 1 BEX 42803 – UTILISATION OF ELECTRICAL ENERGY