Case Study: Design and Implementation of IEC 61850 From Multiple Vendors at CFE La Venta II

The IEC 61850 standard provides methods of developing best engineering practices for substation protection, integration, control, monitoring, metering, and testing. Comision Federal de Electricidad (CFE) chose to build their newest integrated transmission protection and control network with IEC 61850 and evaluated the technology for possible future inclusion into their design standards. The primary IEDs chosen for protection were selected from the devices that have been approved by the customer and that also support IEC 61850. For the La Venta II project, the primary focus was to include IEC 61850 devices from as many vendors as possible rather than using traditional design criteria. In addition to the primary protection and control equipment, the customer invited all vendors to submit IEDs to be connected to the network to demonstrate their ability to communicate IEC 61850. Additional IEDs were added in an auxiliary bay because the design constraints required that the core of the network be useful and effective; it is not a demonstration control system but a pilot project to gain experience with the new standard. This system integrated 24 devices from 9 different product platforms provided by 6 different vendors. The implementation was completed in four months and included newly released products from some vendors, involved staging device communications over the Internet, and relied on contributions from engineers in seven time zones. IEC 61850 is a very large standard with seven different protocols within it. End users implement different combinations of the protocols and the different features they provide. Therefore, it is important that end users not only specify that they want to use IEC 61850, but also what parts of the standard they want to use and, more importantly, how they want the system to perform. Throughout the implementation of this project, it became apparent that implementation details left to the discretion of the vendors and not dictated by the standard needed to be documented as requirements to attain the required system functionality. The following is a sample of these details: quantity of client/server associations to the device, quantity of peer-to-peer messages the device will publish or transmit, quantity of peer-to-peer messages the device will subscribe to or receive, number of characters allowed in the device name, run-time device diagnostics, configuration of the device via SCL (substation configuration language) XML files instead of settings