IEC 61850 standards are the global standard for communication in substations. It is gaining popularity in power substation automation and will dominate the future substation automation and protection system design. The standards provide new approaches for protection, control and metering function via communication. The secondary circuits in substation are simplified significantly and the massive hardwired cables are replaced by the high-speed process bus which transmit analogue and binary signals with Ethernet messages. However, the conformity of a device with the standards does not necessarily guarantee the interoperability with devices from different manufacturers. The use of devices compatible with IEC 61850 standards presents a challenge to many system integrators, especially due to lack of familiarity with features such as Generic Object Oriented Substation Event (GOOSE), reporting, Sampled Values and the need for system redundancy. To facilitate a smooth implementation, all the features and the data exchanges between devices need to be tested to ensure the system operates correctly. This project was carried out to study the protection performance of secondary schemes with IEC 61850 process bus architecture in substation. The tests were performed including current differential protection and distance protection on a transmission substation of the type used in the UK on the transmission network. The protection schemes were tested under IEC 61850 environment with multi-vendor IEDs like Alstom MiCOM IEDs, NARI IEDs with the OMICRON test set. More tests were carried out to verify the interoperability and the performance of time-critical messages were evaluated under different network architectures. The impact of the background traffic on these two messages was investigated and the response of the IEDs when the Sampled Values packets were lost or overwritten was recorded and provided to utility as a reference. This project also presented a technique to assess the performance of Merging Units from different manufacturers, when operating with Intelligent Electronic Devices (IEDs) performing a distance protection function. The performance of the process bus with parallel redundancy protocol is evaluated using a closed loop approach involving a Real Time Digital Simulator. The results indicate that protection using process bus communication is feasible, and meets grid code requirements when implemented with commercially available products. It was found that process bus operation is robust, even with network traffic conditions far beyond what would be experienced in an active substation.

A real-time simulator (RTS) with digital and analog input/output modules is used to conduct hardware-in-the-loop simulations to evaluate performance of power system equipment such as protective relays by exposing the equipment to the simulated realistic operating conditions. This work investigates the use of RTS to test relays with single-pole-switching (SPS) feature. Single-pole switching can cause misoperations due to fault arc during reclosing of the breakers. Through this investigation, a test procedure appropriate for the testing SPS relays has been developed. The test procedure includes power system modeling for real time simulation, relay test setup, and test plan. HYPERSIM real-time simulator was used to model an actual power system. Transmission lines, three-winding transformers, and induction motor were modeled with actual parameters. Models for fault arc in HYPERSIM real time simulator were developed. Test set-up for evaluating relay performance and wiring drawings for connecting relay in closed-loop to the simulator were developed.

Protective relays are important parts of the power system. The protection guards valuable equipment, and protective relays play a vital role in performing the task. The relay detects fault conditions within an assigned area, opens and closes output contacts to cause the operation of other devices under its control. The relay acts to operate the appropriate circuit breakers to prevent damage to personnel and property. To ensure consistent reliability and proper operation, protective relay equipment must be evaluated and tested. The importance of the relay evaluation issue is linked to capability to test the relays and relaying systems using very accurate waveform representation of a fault event. The purpose of testing protective relays is to ensure correct operation of the relay for all possible power system conditions and disturbances. To fulfill this purpose, relay testing in varying network configurations and with different fault types is required. There are a variety of options that have different performance potentials and implementation constraints. Use of digital simulators to test protective relays has proven to be an invaluable mean to evaluate relay performance under realistic conditions. This thesis describes a new methodology that attempts to improve the existing practices in testing relays by using advanced digital simulator hardware, different software packages for network modeling, and new software tools for generating and replaying test waveforms. Various types of microprocessor relays are tested and evaluated through the set of scenarios. New methodology that combines different software packages to facilitate particular testing objectives is applied.

Master's thesis deals with use of electronic instrument transformers (sensors) in the protection system in medium-voltage substation. Substation consists of 2 incoming feeders, 2 outgoing feeders for motors, 2 outgoing feeders for power transformers, measuring, bus coupler and bus riser feeder. Incoming feeders are connected to distribution system E.ON by cable lines which were proposed. Protected machines (power transformers and motors with rated power) are connected to switchgear panels of UniGear ZS1 type by cable lines too. Proposed protection system is based on the short-circuit conditions, standard CSN 33 3051 recommendations as well as theoretical backgrounds acquired from technical papers and other publicated literature according to the bibliography. For selected protection functions are defined their parameters. Control, monitoring and protection functions provides REF 542plus relay. Consequently, secondary tests which are part of the commissioning, are given in the practical part of thesis. Secondary tests were performed by relay test system FREJA 300 by Megger. Results of tests are displayed in tripping characteristics.

The thesis is focused on the protection concept for medium voltage substation. The first theoretical part of thesis describes given medium voltage substation. Substation consists of two incoming feeders and six outgoing feeders. Due to the size of the substation was selected one outgoing feeder which is the subject of description and protection concept. Next part of the thesis is a description of the protective functions used to protect the elements in the selected feeder. This part contains a detailed description of the function and setting options for protection. The main part of the thesis describes calculation of specific protection functions and consequently with secondary testing of protective functions. Tests were performed on protective functions in the digital protections REF615 and REM620. The final part of the thesis deals with the evaluation of the secondary test results and verification saturation of the specified current transformers.