Multi-Service IP Communication for Metering and Grid Information JOHN-PAUL KNAUSS Principal Distribution Automation Engineer, National Grid TOM JOHNSON Smart Grid Automation Manager, Itron WHITE PAPER
TABLE OF CONTENTS Executive Overview 3 Introduction 3 Multi-Service Applications 3 Energy Savings 3 Reliability Improvement 4 Asset Management 4 Operational Efficiency 4 Internet Protocol Network Architecture 4 Network Test Plan 5 Network Test Results 5 Conclusion 6 Acknowledgement 6
Sensors and Faulted-Circuit Indicators Power Quality VVO EOL Voltage Endpoints Operational Efficiency Energy Savings Asset Management Reliability Improvement Asset Management and Transformer Monitoring Distributed Intelligence Figure 1. Multi-Service Applications EXECUTIVE OVERVIEW As utilities look for cost-effective solutions to improve grid operations, distribution automation (DA) is a key technology to aid in increased operational efficiency and performance. Conventional utility approaches have deployed separate, isolated, communication networks for AMI systems and DA equipment; this comes at a significant cost and with additional integration complexity. As a result, utilities have an increasing interest to leverage new technologies for their AMI communication investment that also enable DA applications. This approach enables implementation of multi-vendor devices and systems for data integration, and best-in-class grid-optimization software applications to deliver multi-user accessibility, grid situational awareness, and reliability. A network which can solicit information from diverse data endpoints can provide both metering and conditional awareness of the distribution system and readily exchange data both securely and reliably through common standards that provide for interoperability within a more intelligent electrical infrastructure. IPv6 can deliver these desired capabilities on a large scale to offer best-in-class network management, quality of service, and enhanced network security. An open, standards-based IP network can cost-effectively achieve these overall objectives within a multi-service communication architecture that delivers both AMI and DA applications on the same communications platform which demonstrates the co-existence of AMI and DA traffic from diverse data formats to securely and effectively translate and transport AMI data along with DNP3 data over an IPv6 unlicensed 900mHz RF Mesh network. This paper will review the distribution data collection methods, network optimization and traffic prioritization techniques, and communication performance results for monitoring and control of distribution equipment that co-exists with AMI traffic over a single IP network. INTRODUCTION Multi-Service communication networks are providing new technology for utilities to leverage a single platform network investment to address both AMI and DA applications that provides interoperable open standard data that can be accessed by multiusers for grid awareness, reliability, and optimized energy delivery solutions. MULTI-SERVICE APPLICATIONS Today, utilities have the capability to access communicationenabled IP data from diverse data endpoints that can provide both operational and non-operational data to help utilities optimize energy delivery performance and provide multi-users valuable information to gain insight to grid performance, decision-making, and historic analytic information for energy delivery optimization. Energy Savings Access of meter operational data values provides utilities with both consumption and voltage delivered values that help utilities manage voltage profile data via strategies including Conservation Voltage Reduction (CVR), and Volt-Var Optimization (VVO). 3
The average voltage delivered to the US end-user customers is 122.5 volts with guidance of ANSI C84.1 for delivered voltage to end users between 126-114 volts. When utilities can manage service voltage between 120 and 114 volts, utilities can achieve generation savings and release system capacity. A utility can achieve on average a four percent peak load generation savings for a one volt reduction to delivered voltage, as well as a two percent capacity savings on a constant 24/7/365 model. A multi-service communication network can provide the end point information that helps utilities implement CVR/VVO strategies to optimize their energy delivery model in near real-time performance. Reliability Improvement In addition, utilities can leverage a multi-service communication network to connect reliability intelligent controls to provide both automation and control to improve switching and capacity allocation. As a result, coordination of centralized and distributed intelligence can manage grid devices with communication network message prioritization and quality of service that enable utility feeder automation software to optimize grid reliability over a single network. The communication network may comprise 900 mhz RF Mesh, cellular, Wi-Fi, Wi-Max, and other communication technologies that can leverage open standard IP data. The end result is a network that allows intelligent controls to provide both local control and centralized/distributed optimization through IP data management that uses both exception-based reported such as generated with Distributed Network Protocol (DNP) or scripted performance such as leveraged with controls that use IEC61850 GOOSE messaging. Asset Management The IP connectivity of line sensors and transformer monitors enables more optimization strategies related to both multi-service and comparative modeling that improves grid awareness and asset performance. For example, utilities can examine plug-in electric vehicle consumption with transformer load performance to determine the impact of quick charging electric vehicles on the energy delivery provided from the service transformer. In addition, utilities can gain insight to potential tamper/power diversion issues through the system comparatives between transformer load sensing and the AMI endpoint consumption metrics. This comparative may indicate a potential endpoint value excursion which could indicate a consumption or device irregularity for future utility inspection. Further, IP communication can help utilities with alarms and conditioned-based maintenance prioritization based on information delivered from SCADA or Outage Management Systems that can direct utilities to proactive maintenance verses reacting to a larger scale problem. Operational Efficiency Utilities can leverage a multi-service communication network to gain visibility to areas/conditions of the grid that would otherwise be difficult or impractical. For example, a utility may use communication-enabled faulted-circuit indicators or load sensors to track per phase conditions and outages. By understanding these conditions, utilities can improve fault tracking and improve operational efficiency through fault assessment, vegetation management, and improved fault location information. As a result, utilities can reduce the likelihood of faults through sensor information and when a fault occurs, the utility will have improved visibility to the fault condition and location. INTERNET PROTOCOL NETWORK ARCHITECTURE Internet Protocol (IP) is a common message format used with many utility assets including intelligent electronic controls, and more recently, smart meters. A common IPv4 message includes 32-bit address structure represented in 8-bit segments such as the address represented below: IPv4 structure: 192.168.010.010 However, due to huge volume of electronic devices over multiple industries, there is a shortage of IPv4 addresses. As a result, IP structure is being modified with the introduction of IPv6. An IPv6 address is a 128 bit message address which is represented in 16 bit segments such as the address represented below: IPv6 structure: 21DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A The benefit of an IPv6 message is that it contains: Simplified packet header for routing efficiency Mandatory IP Security (IPSec) implementation for all IPv6 devices Improved support for mobile IP and mobile computing devices Enhanced multicast support with increased addresses and efficient mechanisms The electric utility industry has benefited from the migration from IPv4 to IPv6 address to deliver enhanced network security and efficiency. Within the IP communication network, multi-service applications can deliver information supported via IP messaging instead of through proprietary devices/networks. Interoperable devices and systems can deliver information seamlessly without conversion or translation and future systems and devices built on an open-standard IP platform can perform within an existing openstandard IP communication network infrastructure. Figure 2 represents a simple device using serial and Ethernet open standard interfaces to connect to an IPv6 network via RF Mesh and Cellular networks. The network performance is built upon the dynamic IP message structure and Quality-of-Service (QOS) and device protocol message prioritization tags that correspond with IPv6 message network management may use priority-based data tags such as Differentiated Service Code Points (DSCP) and Per-Hop-Behaviors (PHBs) for two-way data traffic. The IP network architecture is designed to support multiple forms of communication technology and deliver multi-service applications. QoS and message prioritization tags can improve network performance and allow utilities to balance technology and solution optimization with system topology and data models. 4
Figure 2. IP Network Communications NETWORK TEST PLAN While there are diverse testing scenarios in the industry, the testing of the co-existence of AMI and DA multiservice applications over a single IP network using 900 mhz RF Mesh (902-928 MHz band) communication technology has value for utilities. When evaluating the applications that can be supported within a RF Mesh frequency hopping spread spectrum technology, often latency and performance deterioration are concerns for data delivered over mesh for DA applications due to the near real-time performance requirements. Therefore, when examining an open-standard, interoperable IP communication network, two-way response testing may provide insight to data delivered over the mesh with control-based protocols that use exception reporting. The testing scenario used for the live demonstration of AMI/ DA coexistence traffic involves multi-vendor devices and meters communicating with different industry protocols (C12.22 and DNP3.0) to multi-applications residing at the enterprise service bus level head-end application. The applications included both meter based collection software and SCADA/DNP3.0 Master control for DA device monitoring and control.to support an interoperable open standards approach with IP communication, standard interfaces such as RS232 serial and RJ45 Ethernet connections we re used to connect DA devices to the network, and standard meter / radio integration was used for meter mesh communication. A connected grid router was used to securely collect information from DA gateways used for multi-vendor control information and meters. The connected grid router also has connectivity ports for direct connection to controls which could deliver IP data from controls directly connected to a standard interface. The connected interfaces transmitting data from RF Mesh and direct connected devices were managed by a vendor network management system that ensured secure delivery of encrypted data to the head-end processes. The enterprise service bus (ESB) delivered IP data from the field devices and meters to their corresponding applications as called by their IPv6 endpoint address. AMI meter consumption data could be delivered to the AMI services and presented to meter data management/billing/analytic solutions, whereas control information from field devices may be delivered to SCADA or optimization software engines such as distribution management systems or specific applications such as VVO or FDIR. NETWORK TEST RESULTS Network response testing was measured using readily available software and terminal programs to collect response metrics. The results were measured to both the ESB as well as application response to validate interoperability and open standards communication was not limited within the communication stack. 5
The test results measured within the network management system software tracked data transmission between the device and ESB both on data transmission time but per hop on the mesh network. Testing results were reported in the near real-time measurement on average of 500 msec per hop with zero packet loss/error. In addition, data transmission was measured between the device and SCADA DNP Master Application software with 500 msec response and zero packet loss validated via terminal software and DNP master application. Two-Way Traffic Reads IPv6 Packet Response to NMS Figure 5. DNP Master Traffic Diagnostics Figure 3. Network Management System Test IPv6 Packet Rresponse to SCADA CONCLUSION In conclusion, IP communication networks can deliver IP device data from diverse field equipment to support software application systems as follows: A single IP network can support multi-service applications with appropriate latency and response for optimization solutions IP traffic can support both legacy and new/future controls through both IPv4 and IPv6 addressed messages Quality of Service and message prioritization provides mesh network with capability to deliver low latency performance IP Communication networks can exist with single communication technology or be blended for reach or to achieve higher performance requirements ACKNOWLEDGEMENT The authors gratefully acknowledge the contributions of National Grid, Itron, and Cisco resources for their work on the integration and testing of field equipment and systems used in making conclusions used in this document. Figure 4. SCADA Response Testing References available upon request. Itron is a global technology company. We build solutions that help utilities measure, monitor and manage energy and water. Our broad product portfolio includes electricity, gas, water and thermal energy measurement and control technology; communications systems; software; and professional services. With thousands of employees supporting nearly 8,000 utilities in more than 100 countries, Itron empowers utilities to responsibly and efficiently manage energy and water resources. Join us in creating a more resourceful world; start here: www.itron.com CORPORATE HEADQUARTERS 2111 N Molter Road Liberty Lake, WA 99019 USA Phone: 1.800.635.5461 Fax: 1.509.891.3355 While Itron strives to make the content of its marketing materials as timely and accurate as possible, Itron makes no claims, promises, or guarantees about the accuracy, completeness, or adequacy of, and expressly disclaims liability for errors and omissions in, such materials. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, and fitness for a particular purpose, is given with respect to the content of these marketing materials. Copyright 2013, Itron. All rights reserved. 101345WP-01 10/13