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

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

Overview

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.

Use Case

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 10-20 homes

HAN NAN WAN Use Case Residential Areas In Urban Environment Each HAN may cover about 10-30 houses that come within the range of 30-40 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 100-150 houses separated by a distance of 100-300 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

Experimental Setup & Results

Experimental Setup Setup consists of two IEEE 802.5.14 routers, four IEEE 802.5.14 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.

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

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.

Experimental Results Current Consumption of the End-Node

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

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.

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.

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.

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

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

Data aggregation concept

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

Question by Special Reporter

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 70-90 m indoor and approx. 160-190 m outdoors 6LoWPAN: Approx. 800 m for some industrial transmitter modules

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

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.