Over the course of the last decade, IEC 61850 has become the leading standard for electrical substation automation the world over. This thesis presents the work done towards implementing an IEC 61850 sampled values based line protection Intelligent Electronics Device (IED) on a desktop computer. This IED is capable of subscribing, decoding and processing the sampled values published by a source to be used in line protection algorithms. The novel hybrid line protection algorithm implemented in the IED combines a distance protection scheme with a transients-based unit protection method that uses sampled values complying with IEC 61850-9-2-LE. Application of the line protection relay for protecting a series compensated transmission line was examined using hardware-in-the-loop simulations. Results indicate that (i) the implemented algorithms are robust and reliable, and (ii) the class of transients based protection algorithms examined in this thesis can be successfully implemented with IEC 61850 sampled values. / October 2016

At present, there is a widespread use of alternative measurement technologies in electrical networks that include current and voltage sensors. Their use is closely related to the use of IEC 61850-9-2 for data transfer of measured values within the substation for the purpose of protection and measurement. The use of sensors and communication standard IEC 61850 together with high-speed Ethernet will simplify the concept of the arrangement of protection terminals in substations and enable the development of a new protection system based on central protection. The dissertation is focused on protection algorithms, which use the SV according to IEC 61850-9-2, and their implementation into the central protection model. Thesis describes development in the field of protection of substations and the currently available solutions using IEC 61850-9-2 and the principle of central protection. Thesis explains algorithms for selected protection functions - overcurrent protection, negative sequence overcurrent protection, logic busbar protection and differential protection. Further, thesis deals with the programming of protection function algorithms in LabView development environment in the form of a central protection model. The model processes data from a process bus according to IEC 61850-9-2 and sends a GOOSE message over Ethernet in the event of a failure. To verify the correct function of the programmed protection algorithms, a testing procedure was developed using OMICRON 256plus, the current sensor and the merging unit. The results of the testing of the central protection model and the proposed algorithms were compared with the results of testing the currently used protections. At the end, the thesis deals with the assessment of the benefits of central protection for protecting substations and the possibility of further utilization of the central protection model. The thesis highlights a new way of protecting the electrification system using digital data from MU transferred via the process bus described in IEC 61850-9-2.

The Master Thesis deals with a proposal of algorithm of a protective function for assymetric faults location in resistance-grounded medium voltage networks with decentralized measurement of instantaneous voltage and current values. The theoretical part describes a single pole fault in the resistance-grounded network including the network analysis using the symmetric component method. Furtherly follows brief reserse of nowadays considered possibilities of faults location in the medium voltage networks. The proposed algorithm which works on the principle of negative sequence changes and change differencies of voltage and current is described by mathematical operations and flowchart, and it is furtherly tested in the PSCAD simulator on the proposed network model. Also the algorithm is tested in the Matlab program using the real data from the local distribution network Pod Palackeho vrchem where the initial pilot implementation is assumed. The last part of the thesis includes also the algorithm sensitivity analysis.

Thesis (MEng (Electrical Engineering)--Cape Peninsula University of Technology, 2019 / The purpose of an electrical power system is to supply electrical energy to the customers. Power transformers are required to transform the system voltage from generation to transmission and distribution levels. Protection and control systems must ensure that power system high voltage equipment such as transformers operate and deliver save, reliable and secure electricity supply. The aim of the project research work is to develop and implement a strategy, methods and algorithms for monitoring, protection and voltage control of parallel power transformers based on IEC 61850-9-2 process bus standard. NamPower is a power utility in Namibia. The IEC 61850 protocol for electrical substation automation system is used for the protection and control of 5 power transformers operated in parallel in an existing substation system. The IEC 61850-9-2 process bus standard is however not used in regards of Sampled Values (SV). Protection and control devices are connected to a substation communication network, routers and switches using fibre optic linked Ethernet. Inductive Current Transformers (CTs) and Voltage Transformers (VTs) secondary circuits are hardwired to Intelligent Electronic Devices (IEDs) and fibre optic links are not used for this purpose at process level communication. The research focuses on the implementation of the IEC 61850 standard with Merging Units (MUs) and sampled values to improve the existing implemented protection and control system at NamPower. This includes substation communication networks and MUs used for transformer protection, voltage regulator control and cooling fan control. At the present the CTs located at the transformer bushings and switchgear and the VTs located at the switchgear are hardwired to the inputs on protection and control IEDs. The research focuses on issues with the copper wires for voltage and currents signals and how these issues can be eliminated by using the MUs and the SV protocol. The MUs which are considered in this Thesis is to improve the voltage regulator control and the control of the cooling fan motors. The voltage regulator control IED is situated at the tap change motor drive of the On-Load Tap Changer (OLTC). The IED of each transformer is required to regulate the voltage level of the secondary side bus bar it is connected to. All the regulating IEDs are required to communicate with each other and collectively to control the bus bar voltage depending on the switching configuration of the parallel transformers. The control circuit for controlling the cooling fan motors is hardwired. Temperature analogue signal input into a programmable automation controller IED can be used for controlling the transformer cooling fans. A strategy, methods and algorithms for transformer protection, voltage regulator control and cooling fan motor control of parallel power transformers need to be developed and implemented based on IEC 61850-9-2 process bus. Power utilities and distributors can benefit from interpretation of the IEC 61850-9-2 standard and implementing MUs and SV in substations. MUs can be included in the power transformer protection, automation and control systems. A cost reduction in high voltage equipment, substation installation and commissioning costs and better performance of protection and control system are anticipated.

Standard IEC 61850-9-2 definuje přenos vzorkovaných měřených hodnot (sampled measured values, SMV) prostřednictvím sítě Ethernet a využití SMV získaných ze slučovacích jednotek nebo přístrojových transformátorů. Implementace IEC 61850-9-2 závisí na vlastnostech datového souboru, jakými jsou časová synchronizace, počet vzorků a časový interval. Dizertační práce je zaměřena na algoritmy chránění a analýzu vlivu standardu IEC61850-9-2LE na fyzická zařízení ochran s analogově/digitálními vstupními daty o proudu a napětí. S ohledem na narůstající míru interakce mezi fyzickými zařízeními a komunikačními prvky byl navržen test pro analýzu komunikace pro rozvodnu využívající konvenční metody (analogové vstupy) a metody digitální založené na standardu IEC 61850-9-2. Práce dále popisuje funkci slučovací jednotky využívající standard IEC61850-9-2LE. Navržená metoda definuje zdroj SMV a analyzuje přenos dat. V rámci práce byl za využití softwaru Matlab naprogramován algoritmus ochrany. Vytvořený model je schopen vyhodnotit vliv harmonického zkreslení na funkci digitálních ochran a vliv přesycení proudového transformátoru na distanční ochranu. V práci jsou zhodnoceny i možnosti zrychlení testování systémů chránění s využitím neuronové sítě. Závěrečná kapitola se zabývá aplikacemi v reálném čase, využívajícími data z rozvodny v blízkosti Vysokého učení technického v Brně. K přenosu dat z rozvodny do univerzitní laboratoře je zde využíváno SMV přenášených optickým kabelem o délce 16 km. Aplikace je vytvořena v programu Matlab a je schopna číst data z ethernetového portu, dekódovat je, převést z formátu ASCII do desítkové soustavy a poté vykreslit průběhy proudu a napětí. Mezi vlastnosti aplikace se řadí jednoduchost použití, schopnost implementace funkcí distanční ochrany, výpočet RMS hodnot proudu a napětí a harmonického zkreslení, harmonická analýza prostřednictvím rychlé Fourierovy transformace a výpočet impedance poruchové smyčky. Všechny výpočty běží v reálném čase a provedena je i citlivostní analýza modelu.