KPTCL : The Vidyutnet Vista

The

Karnataka Power Transmission Corp. Ltd (KPTCL), the power

distribution and transmission corporation in Karnataka, today is

a Rs 3,000 crore organization catering to about 97 lakh

consumers across the state. The role of KPTCL may be well-known

as a power transmitter and distributor, but its penchant for

using communication technology for the same is lesser known. In

fact, the corporation, during the pre-independence days, was a

telephone services provider in the state. Probably, that

explains the easy adoption of communication technology in its

operations. While the corporation has equipped all the key

officers and engineers in the state wherever possible with

cellular phones (closed user connectivity too) for speedy

consumer services, it has done something credible on the

applications front too. It has built a VSAT-based communication

network to support real-time data applications for power

generation and distribution. This VSAT-based communication

network, baptized Vidyutnet, is the first such network in

the country that has been commissioned to support real-time data

applications for power generation and distribution. There are no

parallels still for this industry. Power Grid Corp., the

national player in power distribution, is also building a

network for similar purposes. But with a difference–it would

not be a VSAT network.

The Architect

& Architecture

The

total project estimated to cost Rs 9 crore was done on a turnkey

basis by HCL Comnet Systems. The network has been designed to

run on the extended C-band frequency, utilizing Viasat’s

Demand Assigned Multiple Access (DAMA) technology in mesh

configuration. The network is aimed at providing a reliability

of above 99.5 percent and to support real-time data, voice, and

fax communication.

The first phase involved

the setting up of the hub station at its Bangalore load dispatch

centre and 40 remote sites covering at the generating and

receiving stations all over the state. The satellite data

channel will replace the existing data channels using power line

carrier circuits. The data channel supports Supervisory Control

and Data Acquisition systems (SCADA) that KPTCL is using for

load dispatch operations. The network is also used for voice and

fax communication. The network management system at the hub

shall have the capability of supporting up to 500 nodes and 1000

satellite channels. Some of the stations to be covered in the

first phase are Bellary, Belgaum, Chikkodi, Hassan, Humnabad,

Kadra, Kustagi, Lingasagur, Mangalore, Munirabad, Mysore, Sedam,

Shahbad, Shivanasamudra, and Supa.

Currently KPTCL hub uses

single- hop DAMA connectivity, which is ideal for high bandwidth

applications like voice and fax traffic, video conferencing, and

Internet/intranet traffic. KPTCL is planning to introduce these

applications over the VSAT connectivity shortly.

Designed as a private

Closed User Group (CUG), the network has a redundant Network

Control System (NCS) at the hub that provides network management

functions, maintains the network, and records status of each

call. The NCS software is menu-driven and user-friendly to

facilitate easy operation, control and monitoring of the

network. It also has graphical representation of frequency

assignments, channel spacing, activated VSATs, and record of all

transactions taking place. The hub consists of a 7 metre

antenna, 400W 1+1 TWTA, up-converters and down-converters in 1+1

configuration, and 1+1 LNAs. The base-band system consists of

redundant hardware to facilitate automatic changeover of the

faulty components without affecting the network traffic. The

network to be implemented in phases has the NCS with

capabilities to cater to future requirements. The network

consists of 3.8 metre antenna VSATs located at generating and

receiving stations. The VSAT equipment interface with telephone

handsets and Remote Terminal Units (RTUs).

The

data acquisition process, involving polling and collection of

packets of data from the SCADA terminals, takes place by using

low bit rate (4.8 Kbps) permanently assigned communication

channels between the remote sites and the hub. Since a data

collection system already existed, data channels had to be

suitably configured to interface and operate with the existing

FEP at hub and RTUs. For Phase I, Karnataka Electricity Board (KEB)

decided to have a pool of 14 voice/fax circuits in DAMA mode,

which have been segregated into three categories on the bases of

connectivity and communication priority. The connectivity

categories being (i) hub and VSATs (ii) VSATs and VSATs in mesh

connectivity and (iii) any VSAT and hub.

Why a

Vidyutnet?



Announcing the launch of the network, N Gokulram, chairman,
KPTCL, said, "Vidyutnet is one of the major steps taken by

KPTCL to improve operational efficiency of the transmission and

distribution network in the state. Satellite technology is

reliable and provides instantaneous connectivity. KPTCL is

actively looking at providing voice and data services at remote

locations to other government agencies as well."

The logic given by

Gokulram is obvious. When an organization requires real-time

updates from over 50 units and offices located in remote

locales, spread across 800 square kilometre area, it is a big

infrastructural challenge. KEB, the utility organization, is

responsible for transmission and distribution of electricity in

Karnataka. The Board consists of a load despatch centre at

Bangalore and various 400 kV power-generating stations and 200

kV receiving stations in addition to a number of administrative

offices. Though at the moment the electricity generation role of

the corporation has been vested with Visweshwarayya Vidyut Nigam

Ltd, KPTCL is responsible for the critical activity of

distribution of power across corporates, residential, and

agricultural sectors in Karnataka. And it becomes very

imperative for a central monitoring body to take stock of the

total power generation levels in the state and distribute it

judiciously. Since generation and distribution of such a scarce

resource requires real-time tracking and reporting, KEB

introduced the SCADA system. The network consisted of one Main

Frame System at the load despatch centre connected to RTUs at

the generating and receiving stations. For optimal utilization

of resources, the Power Line Carrier (PLC) with PLC modems at

both ends was used as the medium for communication. The RTUs or

the "slaves" were connected to the "master"

Main Frame System through a Front End Processor (FEP). Three to

four RTUs form one group, and each group was connected to the

"master" in a star configuration. Data transfer

consisted of queries sent from FEP to RTUs and response from

RTUs to the FEP. Each interaction between the FEP and RTU

consisted of three successive cycles of query and response.

It was planned to convert the network from

a PLC-based network to a VSAT-based network. The first phase of

connectivity consists of 40 VSATs, with the second and third

phase expansion to follow. By implementing a highly reliable

network, KEB expects to reduce administrative costs and ensure

efficient utilization of the resources. The new network can now

give real-time, 24-hour access to reports from all over the

state. In addition to this, the network also provides

toll-quality voice and fax facilities even in the remotest

areas. The network is expected to grow with additional terminals

at other energy distribution/generation sites.