Power System Data Exchange with OPC UA
KALKI Communication Technologies Limited
KALKI Communication Technologies Limited is a technology company founded in 1998, with the vision of becoming the leading provider of standard-based control, communication and computing solutions to OEMs, system integrators and end-users in the energy industry. Kalkitech is committed to providing state-of-the-art solutions to the industry, combining the latest advancement in power system engineering and information technology, based on international standards.
KALKITECH ELTRIX suite of software products provides an intelligent decision support system for energy utilities and consumers for optimizing business and operational objectives under environmental, regulatory and market constraints using complex system models and decision models. ELTRIX is an energy optimization platform through which a number of domain modules enable intelligent operations of power system and ensures optimization of business and operational objectives under real-time constraints.
IEC 61970 CIM & ELTRIX
For standardizing interfaces and data models for power system management and application integration the IEC developed the Common Information Model (CIM). The main objective of the CIM is to reduce expenditure of time and costs for integrating applications into Energy Management Systems (EMS) and Distribution Management Systems (DMS). Beside the Common Information Model, which is the main part of the CIM (IEC 61970-301 and IEC 61968-11), the standard series includes two more interface specifications. On the one hand the Generic Interface Definitions (GID) providing a technology-independent interface for certain types of data and on the other hand the System Interfaces for Distribution Management (SIDM) defining specific interfaces, including XML-based messages and use cases, based on the IEC 61968 function blocks.
ELTRIX is built around the guidelines of Common Information Model and Services for power systems based out of the standards IEC-61970 and IEC-61968. The IEC 61970-4XX series (Component Interface Specification – CIS) specifies the interfaces that a component (or application) shall implement to exchange information with other components (or applications) and/or to access publicly available data in a standard way. The component interfaces describe the specific events, methods, and properties that can be used by applications for this purpose as well as the information content of the exchanges. The purpose of the CIS is to facilitate integration with other independently developed applications or systems.
OPC UA and CIM
The OPC UA developed by the OPC Foundation is now standardized by the IEC 62541. With its information modeling capabilities OPC UA offers a high potential for becoming the standardized communication infrastructure for various information models from different domains. Several information models are already defined based on OPC UA making use of the generic and powerful meta-model of OPC UA. The mapping of CIM to OPC UA is already discussed within the IEC, which is working on a draft version of the mapping (IEC 61970-502-8).
Role of OPC UA in ELTRIX
Generic Data Access (GDA)
- GDA Services are needed to access public data based on the CIM organization of information. This request and reply-oriented service is intended for synchronous, non-real time access of complex data structures.
High Speed Data Access (HSDA)
- Provides access to real time data (current value) including quality & time stamp.
Time Series Data Access (TSDA)
- Designed to enable systems to exchange historical (time series) data.
Generic Eventing and Subscription (GES)
- The GES interface is designed to enable the publishing and subscribing of generic XML based messages like alarms & events.
Benefits of using OPC UA for CIS implementation
- CIM class model and OPC UA class model are similar so that CIM classes, attributes , relationships and CIM objects can be easily mapped to OPC UA address space.
- IEC 61970 CIS interface specifications can be easily implemented using OPC UA specifications.
- OPC UA supports binary protocols and web services.
We have found Prosys OPC UA Java SDK easy to use and it comes with good documentation. Response time of the Prosys technical support team is good. It was easy to integrate since ELTRIX development platform is also Java based. The fact that there is no runtime license cost provides additional value for us.
Kalki Communication Technologies
What is OPC?
OPC and OPC UA (Unified Architecture) are industry standards that enable software to connect devices, machines and systems from different manufacturers using same interface.