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Electrical Network Mapping and Consumer Indexing using GIS

by

S P S Raghav Jayant K SinhaChairman and Managing Director Dy General Manager (IT)

UPCL, Dehradun UPCL, Dehradun

Abstract

Since independence, we have increased our installed power capacity from 1362 MW toabout 110,000 MW and electrified more than 500,000 villages. However, it is a matter of

concern that the annual per capita consumption, at about 350 kWh is among the lowest in

the worldand there are widespread shortages of power in almost all parts of the country.A large number of villages have no access to electricity at all. Households, farmers,

commercial establishments and industries are confronted with frequent power cuts, both

scheduled and unscheduled. Power cuts, erratic voltage levels and wide fluctuations in

the frequency are common. Transmission and Distribution (T&D) losses, excluding theft,are as high as 27.8%. In fact, electricity theft alone causes state utilities to lose over Rs

20,000 crores annually. To make matter worse only 55% of energy generated is billed

and a much lesser 41% is realized in revenues.

The present paper analyzes the present power scenario and the role of GIS in

spearheading the Distribution reforms processes to improve the power industrysviability. To achieve this, IT can play an important role with the use of modern tools and

technology. In fact, given the geographical spread and diversity of power distribution

system, GIS has the potential to revolutionize the reform process in areas like consumer

indexing, distribution network mapping, asset and work management, enhancing billing

and collection efficiency and managing consumer relationships. Therefore, GIS is avaluable tool for improved decision-making through efficient MIS.

THE PRESENT POWER SCENARIO

The total energy shortage today is roughly 8 per cent of the total demand and the peak

shortage is roughly 13 per cent of peak demand. Based on the demand projections made

in a Power Survey by the Ministry of Power, over 100,000 MW additional generation

capacity needs to be added by 2012 to bridge the gap between demand and supply. Themajor reasons for inadequate, erratic and unreliable power supply are:

1. Inadequate power generation capacity2. Lack of optimum utilization of the existing generation capacity3. Inadequate inter-regional transmission links4. Inadequate and ageing sub-transmission & distribution network


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5. Large scale theft and skewed tariff structure6. Slow pace of power reforms7. Inefficient use of electricity by the end consumer

As per the report of Ministry of Power, a capacity addition target of 46,500 MW has beenfixed for Central Public Sector Undertakings. At the State level, the SEBs/ State utilitiesand private sector will add another 41,800 MW. An integrated approach, including

capacity addition through nuclear and non-conventional energy also has been planned in

which 6400 MW would be added through nuclear power and 10,700 MW through non-conventional resources up to 2012.

ROLE OF GIS IN DISTRIBUTION REFORMS

Distribution is the weakest link in the chain of power supply. Distribution has been

identified as the key focus area in power sector reforms. T&D losses are in the range of

40-45% and GIS can help reduce losses and improve energy efficiency through itscontribution in the following areas of Distribution reforms:

1. 100% consumer metering and AMR: Installation of meters at all thetransformation stages and in the premises of consumers, with the provision for

accurate meter reading

2. Feeder & DT metering:Installation of static (electronic) meters on all 11 KV out-going feeders and DTs

3. Effective MIS:Both feeder and DT static meters record active energy, powerfactor and load information which can be downloaded to a computer network to

build effective MIS for quick decision-making and improved distribution system

4. Total energy accounting:Energy received in each 11 kV sub-station and 11 kVout-going feeders, energy billed and T&D losses at each feeder and DT shall be

properly accounted for.

5. Installation of capacitor banks & network reconfiguration:Installation ofcapacitors at all levels, reconfiguration of feeder lines & DTs in a way as to

reduce the length of LT lines thereby reducing ATC losses

6. High Voltage Distribution System (HVDS):Installation of small energy efficientDTs supplying power to 10 to 15 households only, re-conductoring of overloaded

sections, digital mapping of the entire distribution system and load flow studies tostrengthen the distribution system.

GIS can help in achieving the above reforms objectives through various applications:

1. Creation of consumer database and consumer indexing: Indexing of all theconsumers in all categories so that the consumers can be segregated feeder-wise

and DT-wise is necessary. The consumers are mapped using GIS technology and


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identified based on their unique electrical address, called Consumer Index

Number (CIN).

2. Mapping of Sub-transmission and Electrical Distribution Network: It is equallyimportant to have all the 33 KV substations, 11 KV feeders, DTs and LT feedersdigitally mapped and geo-referenced.

3. Load Flow Studies: Having done so, load and consumer profile can be studied andinferences drawn for rectifying imbalances in the network, load analysis in variusnetwork segments and load rearrangement.

4. Load Forecasting: GIS becomes an effective tool in optimal design and choice ofsubstation location, demand-side management, future load assessment and load

planning.

5. Management Information System (MIS): Based on inputs from GIS, which isregularly updated and monitored, a robust MIS can be built for analyzing and

reducing ATC losses, improved revenue billing and collection and load demand/

supply analysis.GIS APPLICATION IN MAPPING OF NETWORK AND CONSUMERS

GIS technology can be effectively used for correct marking of the jurisdictionvarious Distribution Circles on Geographical Area Map. GIS mapping of Sub-

transmission and Distribution network from 33 kV substations down to LT

feeders becomes handy in proper identification, locating and documenting ofelectrical network assets. All the existing connections and consumer details can be

graphically displayed on the GIS map linked to the database. The mapping of

electrical network on GIS base maps and linking with the indexed consumerdatabase is a multi-step process:

1. Develop Database of Electrical Network from 33 kV to LT System withrelated parameters of Lines, Substations and Distribution Transformers

2. Develop Consumer Database based on the Physical, Electrical andCommercial parameters of the consumers and linking them on GIS map

3. Segregation of Consumers - 11 kV Feeder-wise and DistributionTransformer-wise - to evaluate energy supplied, billed and system losseswith rendering and visualization on GIS map

4. Superimposition of GIS-based Network and Consumer mapping databaseon a scale of 1:4000 or better

5. Evaluation of feeder-wise and DT-wise Energy Losses, correlating withload flow studies and their depiction on GIS map

Mapping and Indexing of Electrical Consumers


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The purpose of GIS Mapping and Indexing of the consumers is to identify and

locate all the consumers on geographical map, which are being fed from theDistribution Mains. There may be cases where electric connection exists but it

does not exist in the utility's record. It may be a case of unauthorized connection

or non-legderized connection. On the other hand, there may be cases where a

connection exists in the utility's record, but it may not exist physically at site.Following reasons could be attributed for such anomalies:

1. The connection might have been disconnected long back but the recordmay not have been updated.

2. It may be a case where the address and other details of the consumers are

not correctly recorded.

Using GIS, the LT lines coming out from Distribution Transformer and all serviceconnections from the LT mains can be checked with reference to the consumers

connected and accordingly the consumer database can be updated.

Mapping and documentation of Electric Network

The complete electrical network and network route are digitized and mapped on asuitable scale over the base map, using suitable GIS software, so that the changes

in the network can be timely and correctly updated on a periodic basis. Through

software application, queries can be generated to find out the network details like

the make and specifications of network elements, the length of feeders and LTconductors, number of transformers and breakers on any section of the network.

The network database should have the important details of 33 KV substations, 11

KV feeders, Distribution Transformers and LT lines.

Feeder-wise and Distribution Transformer-wise consumer segregation

To identify the areas of high losses, it is essential to segregate the energy input

and consumption Distribution Transformer-wise and 11 KV feeder-wise. The

losses are assessed by subtracting the total energy utilization of the consumers

from the energy supplied to the respective Distribution Transformer and 11 KVFeeder. Using GPS-based survey of 11 KV feeders, DTs and LT poles, the

connected consumers can be identified on the GIS map and segregated

Distribution Transformer-wise and 11 KV feeder-wise.

Load Flow Study and Load Management

The purpose of load flow study is to eliminate overloading of the network,

minimize technical losses, overcome low voltage problems and avoid unbalanced

loading of Distribution Transformer and LT network in order to achieve optimumutilization of Transformer and network capacity. GIS data of electrical network

and consumers can help in the following exercises required for Load Flow Study:


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1. Evaluate 33 KV, 11 KV and LT feeder-wise technical losses2. Identify the network section overloaded or having high technical losses

3. Identify the area of unbalanced loading of Distribution Transformer andLT Network and take corrective action to minimize technical loss and

achieve optimum utilization of transformer's capacity

4. Work out voltage regulation of the network and identify the areas having

high voltage drops and suffering with low voltage problem.

Based on the above information, alternate arrangement of supply to

important areas can be made in case of outage of part of existing feeding

network. Also, augmentation of the network can be effectively planned tocater for the increase in projected load.

THE ROORKEE EXAMPLE

In the Roorkee circle of Uttaranchal Power Corporation Ltd (UPCL), with a consumer

base of 1.2 lacs, GIS technology has been effectively used for the following activities:

1. Meter Installation Survey:This was done to find out the condition of the meteringequipment at the consumers premises and also update the correct consumer

details in the database using GIS tools.

2. Network Mapping: The location coordinates (Latitude-Longitude) of everyconsumer and electrical network element, from 33 KV sub-station through 11 KVfeeder down to DT and the nearest LT service pole has been plotted on GIS map,

with the following features:

a. All the network elements are identified and a database developed to recordall the technical attributes of the network element.

b. All the network assets have a unique identification number. The networkdatabase has a linkage with consumer database.

c. The network database is having a GUI interface where all the childcomponents are shown as subset of the parent. When a parent is selected

the entire child components can be seen in the left pane. The graphical

symbol of the parent component is shown as expandable.d. In case of network reconfiguration where some components are

electrically connected to a new parent component, then all such child

components can be selected in the left pane can be dragged and dropped tobe new parent component. The database gets immediately modified to

show new electrical connectivity.

e. The entire electrical network has been mapped on a scale of 1:4000. Whenthe DT is selected on GIS map, then all the LT lines connected to that DT

and corresponding LT lines are shown.


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3. Consumer Indexing:A unique Consumer Index Number (CIN) has been providedto all types of consumers and the consumer/ network database has been developed

for correlating each consumer to the corresponding electrical attributes, using GIS

tools to query and retrieve information. The methodology adopted for the exercise

has been enumerated below:a. A detailed door-to-door consumer survey was carried out for the creationof consumer database linked to DT (for LT customers) and linked tofeeder for HT consumers

b. All consumers were allotted a unique Consumer Identification Number(CIN) based on the electrical address of consumers.

c. The information of the consumers network connectivity has beenmaintained in the database.

d. The consumer database has been linked to the network database for thepurpose of defining the consumer's electrical connectivity.

4.

Distribution Network Modeling: The electrical assets like Sub-stations, 11 KVfeeders, DTs, Poles and LT feeders have also been uniquely codified and modeledwith the help of GIS and GPS technologies.

5. Load Flow Analysis: This is being done with the help of electrical databaseimported from GIS map. It plays a key role in determining technical loss,

planning and optimization of distribution system.

CONCLUSION

GIS can effectively manage information on the distribution of electricity to consumers

and information describing the attributes of each consumer such as location andconsumption pattern. Improving the performance of distribution systems to meet the

required target is a matter of selecting the most cost-effective and appropriate technologywith right operating practices. The distribution systems tend to be very extensive with a

long life span for conductors and installations.

It is not sufficient to analyze how a particular portion of the network may be modified toimprove its performance today, rather in determining the optimal solution based on future

demand scenario. GIS technology helps in fast, accurate and reliable data management.

Since the sub-transmission and the distribution network of a power utility have ageographical reference, it is beneficial to create the network on GIS map and constantly

update the same as per field parameters. With periodic updating and monitoring, GISmapping of the Electrical Network and Consumer database helps in improved loadmanagement, loss reduction, better revenue realization, asset and work management and

possibly better consumer relationship.

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