Enabling Utility GIS for Energy Audit and Network Analysis

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Introduction

Energy Audit and Load Flow Analysis are two vital objectives of the R-APDRP reforms under way in most of the State Electrical Distribution Utilities in India. This is in line with the requirements of reduction in ATC losses and total energy accounting. The reforms are envisaged to be thought about through IT-enablement of utility business processes, in which GIS plays a critical role. The GIS application helps in maintaining indexed consumer database and electrical assets database. The indexed consumers are mapped to their relative source of supply. This is essential for performing energy accounting Distribution Transformer-wise and Feeder-wise. GIS application integrated with Network Analysis module helps in various calculations like technical losses, load flow analysis, energy audit, network optimization and "what-if" analyzes.

R-APDRP is the flagship program of Govt. of India, started in 2009, to transform the ailing power distribution sector in India, improve process efficiencies and make it commercially viable, without compromising with the following main objectives:

1. Provide reliable and quality power supply to all consumers at affordable price
2. Progressive reduction in ATC losses to manageable levels
3. Reduce power outages and interruptions
4. Improve customer services

Energy Audit and Network Analysis modules play complimentary roles for proper estimation of the technical and commercial losses and help in taking appropriate corrective action for improving the performance of the electrical distribution system. They help in capturing and validating energy inputs, energy consumption and other electrical parameters to calculate energy losses in a transparent manner.

Energy Audit and Network Analysis

Energy audit has always been high on the priority among all utility applications. Energy audit module has to be seamlessly integrated with metering, billing and collection with minimal manual intervention. The module has to capture electrical distribution network and energy parameters for feeder-wise and DT-wise loss analysis and identification of sections of revenue leakages. Therefore, 100% metering of consumers, substation feeders and distribution transformers is an essential requirements for total energy accounting. The forensic technical challenge is to effect a seamless integration of the entire business processes – both the new systems and current legacy systems, without the utility changes to discard the latter altar.

Energy Audit module has to work closely with Network Analysis. There are special tools available to provide graphical analysis of distribution network with schematics highlighting attribute data for every substation, connected feeders, DTs, circuit breakers, sectionalizers and auto-reclosures. The network analysis tool uses advance algorithms for calculating phase imbalances, identifying low-voltage or overloaded sections, calculating section-wise loss levels and taking decisions on system optimization through network reconfiguration, capacitor placements and other system improvements measures as per energy audit requirements.

GIS is being leveraged in power utilities for energy audit and network analysis, and emerging as a powerful tool for load planning and management with the aim to improve the quality of electricity supply and related services. The geo-referred electrical network overlay on area base map is handy for the utility in not only managing assets and their maintenance, but also for mapping the electrical consumers to its source of supply for energy audit applications. By integrating electrical GIS with network analysis application, various analytical studies are possible for load flow analysis, short circuit analysis, efficiency calculations and optimization.

GIS requirements of Distribution Utility

GIS application for Distribution Utility is a multi-modular application which components is integrated with core distribution processes like new connection management, meter data management (MDM), billing and collections, customer care, network analysis and energy audit. For better manageability, the GIS application should be configured with parameterized business rules with service-oriented architecture (SOA). The GIS application should be able to cater to the following business process requirements:

  1. GIS based consumer indexing and asset mapping based on DGPS survey, digitization and superposition of geospatial map and data on satellite imagery
  2. Integrated with other utility applications for network and load flow analysis, better load management, prevent revenue leakages and improve services
  3. Able to conduct simulation studies to evaluate the impact of network reconfiguration, re-conducting and optimization
  4. Have in-built custom library of utility-specific symbols to add various network components with stored attribute data on base map
  5. Should have the capability of graphical creation, editing and modeling of distribution network based on GIS data
  6. Have the capability of automatic checking and validation of network topology and data based on network design parameters
  7. Able to perform load flow calculations to provide power flows in MW, MVAR and current in each section, load at each node, voltage and regulation at each node for low voltage, overloading and loss analysis
  8. Provide optimization of network design based on calculations for capacitor placement, switching sequence, defensive device coordination and network restoration actions
  9. Provide automatic checking and validation of network topology and data based on network design parameters
  10. Perform load flow calculations for low voltage conditions, overloading, loss analysis and voltage regulations
  11. Perform "what-if" analysis of distribution network parameters, such as (a) Capacitor placement and sizing, (b) Selective reconfiguration and re-conductoring, (c) Substation sizing and location, (d) Network enhancement, and (e) Network load variation

Utility GIS architecture

To serve the purpose of the Utility in terms of ease of use, interoperability and integration with other modules, the GIS application for the Utility has to be a n-tier, web-based application based on Service-Oriented Architecture (SOA). The various components of this architecture are:

1. Presentation Layer : This layer is for formatting and delivery of information and services as required by the Utility. This layer renders the content in presentable format to the target client devices eg Browser, Laptop, Desktops, etc. As the undering functionalities will be completely decoupled from the presentation technology, new devices or service delivery channels can be easily adopted without impacting the functional components.

2. Application / Business Logic Layer : The application tier consists of COTS server application namely ArcGIS Server and ArcFM Server providing the necessary functionalities such as authentication, geo-processing, metadata management, map rendering etc. Customized interfaces and applications will be developed and exposed to the clients using these components. These functionalities include Map navigation, locater tools, query, editing, tracing, SLD's, versioning etc. It breaks large applications into manageable, autonomous and well contained components of business functionality that can be used in a variety of circumstances as defined in the Process Integration layer. The application layer poses specific components as a service.

3. Process Integration Layer : Process layer provides for modeling of the business processes and their integration. It will enable all the underlying services to be integrated and orchestrated as per SOA principle. Addition of new processes or changes in existing one can be implemented by orchestrating the changes as per the new requirement, eg if the existing collection process requires new payment mode to be incorporated, it would just require new payment service to be integrated with existing process.

4. Enterprise Data layer : The database tier consists of the GIS database including the GIS data store (containing the complete data for the Land base, Network and Consumers), Operational Data Store and Analytical Data Store. All the databases are integrated to each other using Data integration Services. The GIS Data Store is the provider of the electrical network data to the other systems such as Network analysis, energy audit etc. The database tire also includes data authoring stations for the administration and authoring of map data. Thus, this layer enterprises of the data and information aspects within the enterprise. Data corresponding to each application stack is available in this layer. This layer is also be responsible for transferring operating data to analytical systems.

Utility GIS Technology requirements

The GIS platform should support generic GIS components and conform with Open GIS data standards eg Open Geospatial Consortium (OGC). The solution must support the latest Web 2.0 and SOA technologies. This will ensure that the Utility GIS solution can be easily integrated with any SOA-compliant third-party applications. Moreover, the application should be highly scalable and easily configurable solution to meet current and future business needs. SOA-compliance empowers the GIS application to deliver geospatial content and capabilities via Web services. Web services correspond to recognizable business functions and offer a set of protocols by which they can be published, discovered, and used in a standard form. Web services are the building blocks of service oriented architecture (SOA), the backbone of service-level integration. Embracing GIS technology within the context of an SOA enriches the organization's service offerings and improvements overall efficiency, accuracy, and accessibility to organizational business processes. These services can be utilized in a variety of client applications on a middleware integration platform, such as Enterprise Service Bus, especially to meet the following objectives:

1. Integration Capability – The application architecture should provide standards-based integration, without the need for proprietary programming tools.

2. Enterprise Scalability – Use of open standards ensures scalability of the application as per Utility's requirements, and optimizing both deployment and maintenance costs of integrated systems.

3. Customizability – Industry standard solution will ensure customization with minimal efforts and ease of deployment of newer version.

GIS Standards and Interoperability

The GIS software selected for developing Utility applications should be capable of centrally managing geo data, providing better data security and integrity of the vast utility database of distribution network assets and electrical consumers. It should provide access to large volumes of data resources, while reducing storage costs and data processing overheads. It should extend GIS capabilities for mobile work management, increasing the accuracy and value of field data collection and asset monitoring. The GIS software should be scalable and robust, designed to meet the Utility's requirements.

The GIS platform should conform to open standards and enterprise IT frameworks that allow users to incorporate GIS into any application on a variety of computing and mobile devices. It should support Utility's workflows and business requirements, spatial data management, editing, analysis, and display. The interoperability across various business modules is achieved through open IT standards:

1. Web standards, through SOAP, XML, JavaScript, etc.

2. OGC compliance, through GML, WFS, WMS, WCS

3. Enterprise Integration, through SOAP, XML, EJB, SQL, etc.

Data Interoperability eliminates barriers to data sharing by providing state-of-the-art direct data access; data translation tools; and the ability to build complex spatial extraction, transformation and loading (ETL) processes. It allows the use of any standard GIS data, regardless of format for mapping, visualization, and analysis. The geospatial capabilities must be built using open, standards-based application program interfaces (APIs). In addition, it should allow distribution of data and services through interface for managing geo-databases.

GIS for electrical utility should have the capability for modeling, editing, maintaining, and managing electrical asset data in an enterprise system. It should provide extensions for feeder management and network analysis. It should include tracing tasks to automate utility operations and an extended set of editing tools. It should facilitate geographic data creation, network mapping and network analysis and allow integration of multiple calculations such as voltage drop, load flow, fault current, load management, network optimization, etc.

Conclusion

In Electricity Distribution Utility, it is a fundamental requirement to have a proper energy accounting and auditing system, aided by distribution network analysis on GIS platform. This can be achieved by automating the distribution value chain using open- standards architecture and appropriate technology. A high level of integration is required using enabling features and web services for timely and accurate recording, processing and mining of data for energy audit and analysis. The process integration envisions the solution to be designed in a multi-tier, web-based and service-oriented architecture (SOA) model. Enabled by GIS, Energy Audit and Network Analysis modules can be seamless integrated with meter data management, billing and collections, asset management, indexed consumer database and electrical network mapping on a middleware enterprise service bus. Standard plug-ins, business APIs and inter-operability standards like WSDL, UDDI, XML and SOAP facilitate this integration process.

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