1. Mrityunjai Tiwari, Sukumara T, Sasi SR Kumar /Presented to CIGRE Colloquium, Mysore, 14.11.2013
Adaptability of Wireless Sensor Network for Integrating Smart Grid Elements in Distribution System
D2-01_18

2. Table of contents Overview Use Case Experimental Setup
Experimental Results
Analysis of suitability of WSN technology
Data aggregation concept
Question by Special Reporter
Conclusion

3. Overview

4. D2-01_18
Overview
The paper emphasizes on our experimental results of WSN (Wireless Sensor Network) based on mesh topology and protocol stacks that can fit on the WSN physical layer framework, thereby enabling features such as Self-healing, automatic role assignment, selection of frequency band which has least congestion etc.
The prototype setup simulated mesh topology based WSN consisting four Modbus slaves devices and a Master device.
The application was tested for data latency for a given amount of data length, network range in a given terrain condition by checking the ‘Packet Error Rate’(PER), ability and time taken by an isolated node to re-join the WSN.

5. Use Case

6. Residential Areas In Urban Environment
Use Case
Residential Areas In Urban Environment
NAN
NAN
HAN
HAN
NAN
WAN
HAN: Home Area Network
NAN:Neighbourhood Area Network
WAN: Wide Area Network
Building consisting of homes

7. HAN NAN WAN Use Case Residential Areas In Urban Environment
Each HAN may cover about houses that come within the range of m.
HAN
Multiple HAN shall communicate with each other through NAN. An example of such an arrangement can be areas consisting of many housing societies and each having houses separated by a distance of meters.
NAN
A city may have various NAN and all these NAN shall be a part of city wide network WAN. The nodes in WAN will be the coordinators of each NAN. These nodes when geographically placed at a uniform distance will act as a gateway to various NAN and thus HAN.
WAN

8. Experimental Setup & Results

9. Experimental Setup
Setup consists of two IEEE routers, four IEEE end nodes .
All the end nodes are connected to Intelligent Electronic Devices(IED) which are connected to Modbus Sensors. Each IED serves as a Modbus Slave or a Modbus server.
The SCADA server acts here as the main co-ordinator for the network and also serves in the capacity of Modbus Master or Modbus Client.

10. Network Elements Description Selects the radio channel for the network
Coordinator
Selects the radio channel for the network
Starts the network
Allows other nodes to connect to it
Router
Relays the messages to other nodes
Allows end nodes to join the network
End-Node
Mainly gathers the data from the sensors and send them to routers and coordinators

11. Packet Error Rate (PER)
Experimental Results
Packet Error Rate (PER)
As the distance between the end-node and the router increases, the PER also increases to a point when it reached 100% indicating complete frame loss. It is evident from the result that the maximum distance between any two nodes of the WSN under experiment is approximately 200 m.

12. Experimental Results
Current Consumption of the End-Node

13. Activity of End-Nodes
How an End-Node saves energy??

14. Network Auto- reconfiguration & Self-Healing
Experimental Results
Network Auto- reconfiguration & Self-Healing
The self-healing characteristic of WSN is a notable feature for the integration of smart grid elements
An important aspect that should be considered while engineering the WSN is that the new parent node must exist within the reach of isolated node because of the router failure.

15. Experimentation on Co-Existence and Data Integrity
Experimental Results
Experimentation on Co-Existence and Data Integrity
The PER for each of the network elements remained Zero percentage even after increasing or decreasing the distance ( from 20 to 50 m) between the networks and isolating them.
The PER of Zero percentage for any distance between the elements of the different network provides substantial evidence for the stable data integrity of WSN.

16. Experimentation on Security
Experimental Results
Experimentation on Security
Unauthorised access was attempted by a router A which was in a closer vicinity to the end node and offered the end node E with higher and better signal strength.
Once the end node detected that the key exchanged by the router A was not an authentic key, it triggered an alarm throughout the system declaring an unauthorised access and also ensured that no data was exchanged with this unauthorised router.
The end node continued its data exchange with the coordinator through an authorised router B even though its distance was more than that of unauthorised router.

17. Analysis of suitability of WSN technology for integrating secondary distribution segment use cases

18. Parameters that should be considered
Analysis of suitability of WSN technology for integrating secondary distribution segment use cases
Parameters that should be considered
Following important parameters should be considered for analysing the suitability of WSN for Distribution Automation Segment :
Range
Security
Interference
Power Consumption
Capacity
Two Way Communication
Network Latency

19. Data aggregation concept

20. Data aggregation concept
A novel approach
T= Total time for the data to reach the destination
PCi = Path cost for ith node
PTRp= Residence time for pth packet
M= Total number of Routers
UPc= Uplink path cost between the destination and its immediate parent node.
PTd= Time for processing at the destination
By knowing the number of child node packets that a router can aggregate and send, the latency of the network can be reduced.
Where,
< T

21. Question by Special Reporter

22. Question by Special Reporter
Expected comparison of network coverage performance for different WSN technologies
Bluetooth:
Class 1: 100 meters at 100 mW
Class 2: 10 meters at 2.5 mW
Class 3: 1 meter at 1 mW
Wireless LAN:
802.11b/g WAPs and routers support a range of up to 46 m indoors and 92 m outdoors.
802.11n WAPs and routers support a range of m indoor and approx m outdoors
6LoWPAN:
Approx. 800 m for some industrial transmitter modules

23. HSDPA vs. GSM/GPRS
Source: Can 3G technologies benefit India?- G Venkatesh & Ashwin Ramachandra

24. Conclusion
WSN features comply with various smart grid requirements. WSN provides a network communication framework and can support the implementation of various features such as data aggregation thereby making WSN a potential candidate for future smart grid communication.