Upload
manjunath-ds
View
226
Download
0
Embed Size (px)
Citation preview
7/31/2019 Concepts and Principles (2)
1/38
Concepts and Principles of Distribution LossReduction
T Raghunatha
Joint Director
Central Power Research Institute
Bangalore
Best practices in Distribution loss reduction
7/31/2019 Concepts and Principles (2)
2/38
Installed
Capacity=182689 MW
T&D Losses:25.47 A &TC Losses: 28.44%
Peak Shortage: 12.7%Per Capita Consumption : 733.54units
IndianPower SceneIndian Power Scenario
7/31/2019 Concepts and Principles (2)
3/38
Frequency fluctuations 2 HzVoltage fluctuations 10% - 40%
Statistical non-availability About 200-800 hours per
year
Technical transmission
and distribution losses
Estimated 30% from 220
kV to 220V
Commercial losses >20%
From a technical point of view the story was not different as
reflected in the Grid performance.
IndianPower SceneIndian Power Scenario
7/31/2019 Concepts and Principles (2)
4/38
PERCENTAGE TRANSFORMATION, T&D
TECHNICAL LOSSES IN DEVELOPING COUNTRIES
0
5
10
15
20
25
30
35
40
45
R
EP.OFKOREA
CHINA
BARBADOS
BELIZE
THAILAND
TUNISIA
EL-SALVADOR
FR
ENCHGUIANA
BRAZIL
ZIMBABWE
GUATEMALA
PHILIPINES
SRILANKA
INDIA@
PAKISTAN
NICARAGUA
HONDURAS
MYANMAR
%
... Where does India stand globally
7/31/2019 Concepts and Principles (2)
5/38
Loss Scenario in India
Sl No SystemSegment
Existing% Level
Target%Level
Tolerable% Level
1 Trs. System 4.5 2.00 3
2 Sub Trs.System
4.0 2.25 3
3 Primary (HV)
Distn
7.0 3.00 5
4 Secon (LV)
Distn
7.5 1.00 4
5 Total 23% 8.25 15
7/31/2019 Concepts and Principles (2)
6/38
ACS v/s ARRIndian
Power Scene
ACS ARR
2001-02 246 181
2002-03 238 195
2003-04 239 203
2004-05 254 209
2005-06 258 221
2006-07 276 227
7/31/2019 Concepts and Principles (2)
7/38
All India T&D and AT&C Losses
T&D Losses
AT&C
Losses
2002-03 32.54 32.54
2003-04 32.53 34.78
2004-05 31.25 34.33
2005-06 30.42 33.02
2006-07 28.65 30.59
2007-08 27.2 29.24
2008-09 25.47 28.44
7/31/2019 Concepts and Principles (2)
8/38
T&D and Revenue Loss
The total of Technical and Commercial losses are
called Distribution losses
In addition to the above, revenue loss occurs on
account of non realization of billed demand
7/31/2019 Concepts and Principles (2)
9/38
Technical Losses
Every element in a power systema linea transformer etc
consume some energy while performing their expected duty.
Cumulative energy consumed by all these elements
constitute technical losses.
7/31/2019 Concepts and Principles (2)
10/38
AT&C Losses
Example:
Units Input 100 MU Units sold 70 MU
Losses 30 MU
T&D Loss 30%
If Revenue collections are
90% of demand.
Out of 70 MU of sales revenue
is realized for 63 MU.
AT & C losses are 37%.
AT & C is abbreviation for Aggregate Technical& Commercial Loss
7/31/2019 Concepts and Principles (2)
11/3815
LOSSES DEPENDS IN ANY SYSTEM ON
Pattern of Energy Used
Intensity of Load Demand
Load Density
Capability and configurations of T & D system
7/31/2019 Concepts and Principles (2)
12/3817
State-wise T&D Loss (%)
7/31/2019 Concepts and Principles (2)
13/38
19
AT & C Loss
Loss in Revenue due to Non Realization of Billed Demand
Input EnergyEnergy Realized x 100Input Energy
or
1Billing Efficiency x Collection Efficiency
Energy Realized = Units Billed x Collection Efficiency
Technical Loss + Commercial Loss + Revenue Loss due to Non
Realization of total Billed Demand
Ex: Units Input = 100MU Units Input = 100MU
Units (Output) Sold = 70 MU Units Realized = 63 MU,
(90% of 70 MU)T & D Loss = 30 MU AT & C Loss = 37 MU
7/31/2019 Concepts and Principles (2)
14/38
Causes for Technical Losses
Wrong location of DTCs
DTCs are not located centrally and farthest consumersface low voltages
For every 10% voltage drop losses increase by 21% andfor every 20% voltage drop losses increase by 44%
DTCs to be relocated at load center to minimise losses
7/31/2019 Concepts and Principles (2)
15/38
Causes for Technical Losses
Over rated DTCs
Under loaded DTCs are a source for high avoidable
Iron losses
Taking village as a unit the loads can be readjusted
among all DTCs in the village for optimal use of
installed capacity
7/31/2019 Concepts and Principles (2)
16/38
Causes for Technical Losses
Low voltage pockets
Where as the permissible LT voltage variations are +/-
6% the voltages at some points go below 10% and in some
cases even more
Full load current drawn by motors go up by 15% for
every 10% drop in voltage
On load tap changers are not made use of due to certaininhibitions
7/31/2019 Concepts and Principles (2)
17/38
Causes for Technical Losses
Low power factor In majority of Distribution circuits the pf is between 0.65
& 0.75
Low pf contributes to high distribution losses
When shunt capacitors of adequate rating are fixed atload end, experiments showed
10% Improvement in voltage
20% reduction in current
6% overall reduction in energy
7/31/2019 Concepts and Principles (2)
18/38
Causes for Technical Losses
Bad workmanship
Bad joints are a source of power loss
Proper jointing techniques should be adopted for firm
connection
Connections at line jumpers, transformer bushingrods, drop-out fuses, isolators, LT switch etc shall beperiodically inspected.
Timely replacement of deteriorated wires, worn outclamps etc
7/31/2019 Concepts and Principles (2)
19/38
Inadequate conductor size.
Main consideration for selection of conductor is voltagedrop
Approved voltage regulation in distribution lines is +/-8% for 11kV and +/-6 % for LT .
Current carrying capacity at ambient temperatures is also
a consideration. Voltage regulation is
(ES-ER)/ ER
ES - Sending end voltage
ER - Receiving end voltage
7/31/2019 Concepts and Principles (2)
20/38
Standards for 11kV Lines
Length of 11kV line corresponding to different loads
Size of
conductor
kVA-km for
8% voltage
drop at 0.8pf
Max of
length of
line (km)
Load that
can be
connected
(kW)
Rabbit 10,650 30 355
Weasel 7,200 20 360
Squirrel 5,120 15 341
The figures are for a conductor temperature of 600C. For a conductor
Temperature of 500C, the above figures shall be about 3% higher and for a
temperature of 700
C about 3% lower.
7/31/2019 Concepts and Principles (2)
21/38
Standards for LT Lines
Length of 415V line corresponding to different loads
Size of
conductor
kVA-km for 6%
voltage drop at
0.8pf
Max of length
of line (km)
Load that
can be
connected
(kW)
Rabbit 11.76 1.6 7.35
Weasel 7.86 1.0 4.86
The figures are for a conductor temperature of 600C. For a conductor
Temperature of 500C, the above figures shall be about 3% higher and for a
temperature of 700C about 3% lower.
7/31/2019 Concepts and Principles (2)
22/38
44
Way to reduce Technical Losses
By proper planning of system configuration by using
Computer Analysis, LT Lines (Radialy laid) can be
reduced & HT can be increased
Running Express Lines for bifurcation & load sharing
Adding Additional DTCs to Network based on load
growth & locating them near load centers
Judicious selection of DT matching with Maximum
KVA Demand @ good pf
7/31/2019 Concepts and Principles (2)
23/38
45
Use of On load Tap Changers in Power Transformer atHigh Voltage 66/11Kv substation
To compensate for the voltage drop at transformer
terminal resulting in poor regulation
Providing switched capacitors & Automatic
voltage regulators on 11 Kv feeders
Use of Off load Tap Changers in DTCs to
compensate Voltage drop due to Agriculturalpump sets, which may draw more current and
hence double line losses
Way to reduce Technical Losses
7/31/2019 Concepts and Principles (2)
24/38
i) 11 kV Lines
PF KVA Current Line Losses
Kw
Before 0.7 428 38.9 27.2
After 1.0 300 27.2 13.4
46
Improving PF by Series and Shunt Capacitors installed at33/11 kV Secondary Side of Power Transformer
ii) LT Lines
Optimum Rating of Capacitor Bank = 2/3rd of KVAR requirement of that
distribution Network
Optimum Location: 2/3rd Length of Main Distributor from transformer
end
Way to reduce Technical Losses
7/31/2019 Concepts and Principles (2)
25/38
47
1) Use of Best Possible Workmanship
2) Use of Minimum joints and proper techniques like PG
Clamps and Wedge Clamps
3) Avoiding Loose connections to Transformer bushing
stem, Dropout Fuse, Isolator, LT Fuse Kit to preventsparking and heating of contacts
4) Periodical inspection of all joints/connections
5) Replacement of deteriorated wires/services/Materials
timely to avoid any cause of Leaking and Loss of Power
6) Adhering to O & m Schedule for all equipments /
Switchgears
7) Outsourcing and franchising of feeders/Substations
Way to reduce Technical Losses
7/31/2019 Concepts and Principles (2)
26/38
System Planning to reduce Technical losses
Develop SLD for all 11kV Feeders
Collect feeder loadings Calculate the Technical losses for all feeders
Categorize the feeders on their loading and loss levels
Suggest the improvement required for each feeder
Prioritize the feeders based on the benefit to cost ratio To start with pick high loss/heavily loaded feeders and
execute improvement work on them
Have an improvement investment plan for at least 3 to 5
years up front and cover all feeders.
7/31/2019 Concepts and Principles (2)
27/38
Comparison of 11kV & LT line Losses
Contrary to popular belief, HT line losses in rural 11kVfeeders are often higher than LT line losses.
Currents stepped up by a factor of 25 in a 11000/433Vtransformer, does not necessarily imply larger LT losses.
Losses depends on how many DTCs exist and how many
LT feeders are taken out directly from the secondary ofthe transformer.
Let us assume there are n number of DTCs ,
An average two feeders directly come out of thesecondary of the Transformers.
Let I be the 11kV line current.For simplicity
assume that the loads are the same and branch out equally,then the branch currents on the LTs are 25I/2n
7/31/2019 Concepts and Principles (2)
28/38
Comparison of 11kV & LT line Losses
The primary and secondary conductors are of the samecross-section and the LT to HT ratio 4:1,
HT and LT line losses are equal, when
[I x 25/2n]2 x 4R = I2R,
Then, n=25
This indicates that the LT and 11kV line losses will beapproximately same when the number of TCs is 25
With 2 LT Circuits on DTC Secondary, for n>25, LTlosses would be less than HT losses.
7/31/2019 Concepts and Principles (2)
29/38
If the secondary current flows only in one LT feeder fromeach DTC, the equation will be modified into[I x 25/n]2 x 4R = I2R, where n=50
And for n>50, the LT losses would be less than HT losses.
In Rural 11kV feeders,Inmost cases two or more LT feeders branch out of thesecondary of the transformer.
Rural feeders often have more than 50 TCs,
Hence in majority of rural feeders LT line losses arelikely to be less than HT losses.
In Urban feeders, however, the number of TCs aresignificantly less and the reverse would be true.
Comparison of 11kV & LT line Losses
7/31/2019 Concepts and Principles (2)
30/38
Commercial Losses.
Occur on Account of
Non performing meters
Under performing meters
Meters not read
Application of lower multiplication factors
Defects in CT/PT circuitry
Pilferage by manipulation
Theft by direct tapping etc.
W t R d C i l L
7/31/2019 Concepts and Principles (2)
31/38
Way to Reduce Commercial Losses.
DTC wise energy audit
Use quality meters
Strengthen Vigilance squad
Proper consumer indexing
Computerized billing
7/31/2019 Concepts and Principles (2)
32/38
54
1) Accurate Metering
2) Use of appropriate range of meter w.r.t connected load
3) ETV meters with TOD, tamper proof data and Remote
reading facility for HT and High valued services
4) Energy Meters housed on a separate Box sealed and
inaccessible to consumer
5) Multicore PVC Cable used for Service Mains
6) Providing potentials link inside body of Energy Meterrather than inside thermal cover
Way to Reduce Commercial Losses.
d l
7/31/2019 Concepts and Principles (2)
33/38
55
1) Integrated of MBC software along with CAT & MAT
softwares to improve collection efficiency and easy
implementation of A. T. Law
2) Eradication of theft by implementation of ATL and
constant intensive inspection by vigilance squad
3) Implementation of IT measures as BEST PRACTICES
adopted by DISCOMs
4) Outsourcing & Franchising of Meter, Billing and
collection and Energy Auditing and Accounting
Way to Reduce Commercial Losses.
7/31/2019 Concepts and Principles (2)
34/38
Anti Power Theft Initiatives
56
Vigilance Activity has been intensified to reducecommercial losses
11 Police Stations are functioning
Special Courts at District Headquarters have been set upexclusively for speedy disposal of Electricity related cases
Apart from Vigilance Inspections by O & M staff havebeen intensified
Periodical and surprise inspections are being carried out
Meter Testing Division and Vigilance wing
7/31/2019 Concepts and Principles (2)
35/38
MILESTONES ACHIEVED
57
ESCOMs has achieved the following milestones during the last two yearsMilestones:
Any Time Payment Kiosk
Transformer Information Management System
Business Plan (07 -10)
Training to ESCOM Personal
Real Time Remote Automatic Meter Reading (RRAMR) Rural Load Management System
DTC wise Energy Audit
Modernization of Central Complaint system
Energy Saving Initiatives ( Demand Side Management)
Insurance Cover
Customer Interaction Meets
Grama Vidyuth Pratinidhi
Prepaid Metering on Experimental basis
7/31/2019 Concepts and Principles (2)
36/38
Conclusions
58
Reduction in AT & C loss calls for
DTC wise Energy Audit
System Improvement works
LT Reconductoring works Rural Load management System
Introducing HVDS System of distributions
APDRP Works
Rating and Calibration of installations on a regular basis
Reducing the overloaded conditions of existing DTCs byestablishing new DTCs at Load centers
C l i
7/31/2019 Concepts and Principles (2)
37/38
59
Bringing in fresh investments both long term capitaland working capital
Reduction of political interference in day to dayworking
Bringing effective regulatory Mechanisms
Bringing Competition both at generation anddistribution levels
Strict enactment of Antitheft Law in accordance withElectricity act 2003
IT initiatives in Power Sector
Professional Management and change in work culturein Power Sector
Conclusions
7/31/2019 Concepts and Principles (2)
38/38
THANK YOU