This document discusses a proposed wireless communication system for CESC to transmit data from switchgear panels to RTUs. It analyzes different wireless solutions like Zigbee and chooses the ATmega256rfr2 transceiver module. A mesh network design is proposed using this module with coordinator and router devices. Implementing this wireless system would save costs compared to the existing wired system, improve network flexibility, and avoid momentary load shedding during maintenance. In conclusion, the document recommends adopting this wireless communication solution for CESC's switchgear monitoring and control.

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Study of smart grid in
CESC
Project Guide:
Mr. Santanu Sen
Manager, Distribution
automation
Presented By:
Sayak Chakraborty
Electrical Engineering,IIEST Shibpur.

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Introduction:
A smart grid is a modernized electrical grid that uses analogue or digital information
and communications technology to gather and act on information - such as
information about the behaviours of suppliers and consumers - in an automated
fashion to improve the efficiency, reliability, economics, and sustainability of the
production and distribution of electricity.
• A smart grid platform implies the convergence of Operations Technology (OT) – the
grid physical infrastructure assets and applications–and Information Technology (IT) –
the human interface that enables rapid and informed decision making.

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Communication:
• A state-of-the-art communication system has to be efficient, reliable,
secure and high degree of inter-operability is another impotanr
requirement.
The below figure describes the applications of communication in smart
grid and corresponding appliances to implement them:

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• Currently, communication in CESC is highly Dependent On its Fiber Optic
communication network and SDH, PDH. They are integrated to meet the traffic
requirement and there is a Network monitoring system for monitoring the whole
network.
• 2-way voice transmission from central EPABX at CESC house, transmission SCADA,
Distribution SCADA,RMU Automation etc. are done with the help of this network
• Presently a pilot project is being conducted to set up a RF mesh based
communication system to transfer data from AMIs , FRTUs.
• Other important components include GPRS Modems ,Gateways ,routers or switches
which are often used to integrate an isolated component (e.g RTU) to existing
communication network.

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Feeder automation:
• Extends automation downstream beyond the Grid Substation/ Distribution
Station using automated devices, remote control units, versatile communication
technologies and network control system with Feeder Automation software.
• Automated Devices include Line Reclosers, Sectionalizers, Load Break Switches,
Ring Main Units, Circuit Breakers, Capacitor Banks, Line Regulators,FPIs,AMR
installed in Distribution transformer etc .
• Feeder automation makes use of several components like RMU, FRTU, FPI, DMS
,communication links etc.
• With the help of feeder automation the action of fault location isolation and
restoration has reached a new height where power restoration time reduced
from several hours to 8 minutes in case of automated RMUs.CESC currently
have 19 fully automated (motorized RMUs) and has a plan of going for full
automation.

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Demand side management:
• demand side management (DSM), is the modification of consumer demand
for energy through various methods such as financial incentives and
behavioural change through education. Usually, the goal of demand side
management is to encourage the consumer to use less energy during peak
hours, or to move the time of energy use to off-peak times such as night time
and weekends.
• Efficient load-intensive appliances help in DSM.
• Any reactive or preventative method to reduce, flatten or shift demand.One
such application is installing TOD meters in customers’ premises. CESC has TOD
meters for LT commercial, industrial and for other part of the consumer base

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IT Infrastructure:
• IT plays an integrated role in smart grid technology where it works as both the
data management system (ERP,GIS,CIS,EAM) and control system dashboard
(DMS,NMS,MDMS).
• Altogether the concept is called Enterprise application Integration where a
complete database of the utility resides and can be accessed on demand.Even
though There’s no such integrated solution in CESC

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AMI & AMR:
• Smart metering technology is one of the key focus of the utilities that invest in
smart grid deployment. They are digital meters that record real time data and
store or transmit them to pre-assigned destination. Main difference between an
AMR & AMI is that the latter allows TWO way.
• These meters provide different functions like time-of-use pricing information,
demand-response actions, or remote service disconnects.
• CESC Used to have AMRs with a GSM modem based communication facility long
back and currently these modules operate via GPRS service with a back up GSM
connectivity. The system is integrated via a software called INTEGRATOR
• AMI installation currently rolling out as a pilot project in select consumers’
premises. These meters are procured from Landys+gyr,Iskraemeco.

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Conclusion:
• Current disaster recovery system in BCC needs functional enhancement.
• GIS needs functional enhancement as the current system does not integrate all
10 districts ,of which CESC is distribution licencee
• As a forerunner in power sector it’s highly recommended to set up an integrated
platform like EAI for Database management instead of islanded systems,
working discretely.
• Twin communication infrastructure is required for ensuring uninterrupted
system performance

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RTU to Switchgear interface using Wireless IED:
• Figure shown below indicates the present scheme for sending digital and analogue
information to RTU and vice versa.
• Portion to be replaced
• with wireless module
Coupling
relay or
transducer
Hard i/o Marshalling
distribution
frame
Hard i/o Remote
terminal unit
Multi function
meter

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Comparison of Wireless solutions:

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Choice of device:
• As per our problem statement that requires a medium data rate,medium range,
cost optimized solution -- a RF module(2.4GHz ISM band) will best fit our
purpose. After proper market research RF modules that follow ZIGBEE standard
of communication protocol are chosen.
• Important Features that make ZIGBEE suitable for our purpose are as follows:
1.Low power consumption for data transmission within 100m. and provision of
range extension via Mesh Networking.
2. ZigBee is typically used in low data rate applications that require long
battery life and secure networking (ZigBee networks are secured by 128 bit
symmetric encryption keys.)
3. ZigBee has a defined rate of 250 kbit/s, best suited for intermittent data
transmissions from a sensor or input device & therefore suits our purpose.
4. The technology defined by the ZigBee specification is intended to be simpler
and less expensive than other wireless personal area networks (6 LoWPAN).A
switch to WPAN from the current daisy-chained adam module based signal
transmission will make the network more flexible for both operation and
modification as any change can be done via firmware alteration.

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• The device that we have chosen is ATmega256rfr2 from ATMEL as shown below.
The biggest advantage of this transceiver module is its integrated
microcontroller+TRx in a single chip. Therefore no external microcontroller is
required to program the device.
• The board has an integrated chip antenna and an external antenna connector.
For higher gain we should opt for an external antenna.

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• A Rf-mesh based system is designed where the co-ordinator device is connected
to the RTU and Routers are connected to switch gear panels.There may or may
not be any end device.
• Communication between a co-ordinator and a router can be done in two ways.
1.spontaneous mode: routers will keep sending data to RTU via co-ordinator.
2.polled mode: Co-ordinators will make query to the router to send data.
Proposed Network design:

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Cost-Benefit analysis:
• MDF and the wires Cost around 3-3.5 lakhs for a single distribution station &
around 10,000 rs for a single 33KV panel. Wireless modules cost 4000,with some
other protective measures it’ll cost around 5000 each.Thus we can save totally
1.5lakh,50% of total budget.
• Cables in the station, that carry signals to RTU are laid in a particular fashion
such that , if any operation is to be done on them or the MDF or RTU one has to
power off the switchgear panels for a while. This would cause load shedding in a
particular region which in turn lower customer satisfaction.
Had it been a wireless system in place of a wired one ,momentary load shedding
would have been avoided.
• Going for a wireless solution enhances network flexibility. With relatively less
effort one can modify or re-design the whole network as Changing the firmware
of corresponding wireless module would prove to be sufficient

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Conclusion:

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Thank You