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The MV networks operated by ESB Networks (ESBN) exhibit very high levels of static and dynamic asymmetry. Historically, application of arc suppression to such networks was considered impractical or unsustainable. This paper outlines the trials and live earth fault tests that confirmed how modern techniques make arc suppression in such networks successful. Further, the addition of faulted phase earthing...
In this paper, a new algorithm for the differential protection of a power transformer based on the Principal Component Analysis is presented. The algorithm involves the pattern recognition from differential current data. Its purpose is to discriminate between energization and over-excitation conditions and transformer short-circuits. The performance of the algorithm was analysed simulating several...
This paper presents a new, very fast method for selection of faulted circuit in parallel lines for both uncompensated and series-compensated lines. It suits for protection of parallel uncompensated or series-compensated lines and uses one-end phase currents measurements only. The developed algorithm has been tested and evaluated using signals taken from ATP-EMTP versatile simulations. A detailed model...
Current Transformer (CT) saturation may cause the maloperation or operating time delay of protective relays. In this paper, a CT saturation detection algorithm based on wavelet transformation is suggested. The WT (Wavelet Transformation) can be easily implemented with the multilevel filter banks. Daubechies 2 is used as the mother wavelet in the proposed algorithm. A second order Butterworth highpass...
Crete is the largest autonomous power system in Greece with significant RES penetration and expensive oil-fired units. There are concrete plans for interconnecting Crete with the Hellenic Transmission System via High Voltage Direct Current (HVDC) submarine cables. Interconnection plans of Crete with Cyprus and Israel also have been announced. These interconnection plans will inevitably change the...
This paper presents a novel algorithm of distributed bus-bar protection based on admittance to solve the data out-synchronization problem of distributed differential current bus-bar protection. With the introduction of voltage, the relationship between the differential admittance and the braking admittance can be used to realize the distributed busbar protection without data synchronization. When...
A new algorithm for estimating parameters of the fundamental component of a secondary current deformed due to CT saturation is presented in the paper. The algorithm is developed in an innovative 3D methodology where the samples of phase currents are considered as components of a 3D vector. The proposed algorithm can properly simultaneously remove the aperiodic components and distortions caused by...
Application of new architectures of Artificial Neural Networks (ANN) in detection of arcing high impedance faults in MV distribution networks is presented in the paper. These new computational schemes can be used to reliable HIF detection in ungrounded, grounded using a Petersen coil and grounded via resistance distribution networks. The algorithms are tested using data obtained from computer simulations...
All devices in substation environments are susceptible to interference from various sources, such as adjacent power conductors, substation heating supplies running in close proximity to DC wiring, to presence of battery earth fault. Selection of appropriate tripping / inter-tripping devices is of paramount importance to avoid undesirable protection mal-operations. This paper discusses when and where...
This paper introduces a new current and voltage transducer for MV networks which will provide a higher visibility of the operating status of the circuits to which they are connected. The immediate attraction of the system is the ease with which it can be installed both in new builds or retrofitted to existing systems. The unit takes advantage of well-established cable termination technology. It has...
Based on the steady-state characteristics of Distributed Generators (DGs) in a microgrid a fault analysis method has been developed using Matlab-Simulink phasor analysis tool. Droop control and current limiting are included in the steady-state DG models. The method can be applied for both fault and load flow analysis of small and medium scale distributed generation networks in the Simulink environment...
This study investigates a recloser-fuse coordination protection methodology for distributed generation systems. The technique identifies critical margins for proper recloser-fuse coordination and monitors distribution line ratings in real-time. In case of violations, only distributed generators attributed to effectively increasing short-circuit level are disconnected from the grid by gate turn-off...
With the increasing penetration of renewable energy resources and other forms of dispersed generation, more and more uncertainties will be brought to the dynamic security assessment (DSA) of power systems. This paper proposes an approach that uses ensemble decision trees (EDT) for online DSA. Fed with online wide-area measurement data, it is capable of not only predicting the security states of current...
This paper presents a highly integrated sinusoid reference generating system based on Microblaze, suitable for precise testing of protective relays. Microblaze, a soft CPU core, was embedded in a FPGA that integrates an ADC interface, a DAC interface, an EEPROM and other peripherals. The prototype and transfer functions of various types of digital filters were designed with reference to the characteristic...
This paper proposes a hybrid protection scheme for UHVDC transmission line. The proposed hybrid protection scheme consists of a single-ended protection, a pilot protection and faulty pole identification unit. The single-ended protection is based on the attenuation of dc filter and smoothing reactor on high frequency components, while the pilot protection is using the differences of voltage and current...
Coordination between inverse time overcurrent relays within meshed systems are achieved by adjusting two relay settings; pick up current and time multiplier settings. The operating time of these relays is also a function of two additional constants; one represents the constant for relay characteristics and the other one represents the inverse time type. For typical relays, each of these two constants...
This paper addresses reliability, availability of telecom core and data centre power infrastructure. Their potential for improvement by combining different distributed generation sources (DGS) along with commercial AC grid. For this application considered DGS are based on geothermal power, hydropower and diesel generators. Influence on overall electrical reliability and availability of infrastructure...
This paper proposes a reduced model for a modular multilevel converter (MMC) that can be used to evaluate the first transient after a short circuit fault in a DC grid. Detailed modelling of an MMC involves a large number of electrical nodes, hence requiring high computational effort. Reduced converter models have been proposed in the literature. However, calculation times can still be high for large...
Nowadays, Direct Current (DC) power system is paid attention by many engineers since it is considered as the solution against many challenges related with energy efficiency. However, many researches and developments are needed in order to realize DC power system. That is because power infrastructure is based on Alternative Current (AC) system so far. Among DC-related technologies, protection technology...
A novel disturbance identification method for HVDC transmission line main protection is proposed in this paper in order to prevent the mal-operation of protection caused by disturbance. The identification principle is based on the different variation trends of voltage in the cases of disturbance and fault, and this characteristic difference of voltage will be amplified in the IMF with the lowest frequency...
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