In order to guarantee the stability of the power system, the Spanish National Power Plants and Transmission Authorities (UTEs) need to use standard tools to record and monitor the traffic on their HSR/RPR networks. RELY-REC is a time-aware solution that can be used to support continuous monitoring of high-availability Ethernet, intelligent recording and filtering.

Case background

The complexity of modern automation systems requires not only commissioning of equipment before it is put into service, but also continuous monitoring. This approach allows for effective forensic analysis and advanced preventive maintenance based on big data analysis in the event of an accident.

The introduction of new technologies using high availability networks and sub-microsecond synchronization, such as HSR/PRP and PTP, in the IEC 61850 standard for substation automation is beneficial for improving the quality of service provided by utilities. However.This advanced level of digitization also brings with it new technical challenges that require comprehensive means for continuous and decentralized surveillance.

Spain's National Power Plant and Transmission Authority (UTE) utilizes HSR/PRP technology and needs to supply more than 4,000 MVA to more than 36,000 distribution substations. To ensure the stability of the power system, the technicians needed to record and monitor the traffic on the HSR/RPR network using standardized tools and based on a remotely accessible system so as not to affect the performance of the network.

Difficulties and Challenges

First, it is important to consider that in a PTP (IEEE 1588) synchronized power system, it is necessary to correlate all the information being analyzed within the same sub-microsecond time reference used throughout the system. This time reference is shared between merged units, IEDs, remote substations and even higher level smart grids.

Second, in these digital environments, real-time control messages such as GOOSE or SMV are transmitted digitally over Ethernet, and more frequently over zero latency recovery time redundant Ethernet solutions.

To address these challenges, from a system perspective, it is necessary to design configuration recommendations for continuous monitoring based on simple Ethernet, PRP and HSR networks. These settings should allow network traffic analysis for system validation and network assessment. Figures a), b) and c) below depict the time-aware monitoring settings for standard Ethernet, PRP and HSR networks respectively.

Time-Aware Solutions

As shown in the figure above, each continuous monitoring unit (RELY-REC in the figure) is responsible for analyzing, time-stamping, and logging network traffic. In addition, if the network topology requires all nodes to act like a switch, the monitoring device should be able to switch frames based on the expected behavior of a node. Therefore, it is expected that proper correction of the IEEE 1588 frame will be combined with low latency introduced by the node.

The RELY-REC time-aware recorder is a time-aware solution that fully meets customer needs for continuous monitoring in support of high-availability Ethernet, intelligent logging and filtering. While any of the devices are running, read and configuration access is allowed from a remote location via a dedicated communication link. Each RELY-REC recording device can be assigned one or more RELY-REC units depending on the complexity of the desired setup.

The configuration tool allows setting up all network-related functions, including triggering and filtering options. As a result, the device is able to select specific traffic, e.g. GOOSE or PTP to be logged. Filtering and data storage file formats are PCAP-compatible and can be easily defined. The remote PC unit has real-time access to the traffic being logged in the device and the selected files are transferred to the PC at the same time as the event. For basic traffic analysis, the well-known Wireshark tool can be used. IEEE 1588 timestamps are applied to the frames, which are done in a way that can be managed and represented by the Wireshark tool. In addition, advanced testing tools for analyzing GOOSE integrity or network performance are seamlessly integrated into the device's functionality.

In addition, Macronix has launched the RELY-TSN-REC, a logger that can be used to inspect, label and record regular Ethernet and time-sensitive network traffic.

Conclusion

This case study fully illustrates how RELY-REC uses IEEE 1588 timestamps to realize traffic logging in complex zero-drop packet networks. The appliance allows remote configuration of the system and instant retrieval of traffic, using standard filtering and analysis tools, and significantly reduces the cost of forensic and surveillance activities.