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Distributed generation (DG) technology has been rapidly developing and the DG penetration level is becoming higher and higher in power system distribution network in recent years. Due to the access of multiple distributed generators, the traditional instantaneous overcurrent protection may fail to coordinate with each other. In order to solve this problem, this paper studies the fault characteristics...
The increasing DG integration brings many challenges for the protection of the distribution power system, which could change the fault current level and direction in the distribution system. In order to prevent this negative influence of DG and upgrade the protection system performance, a simple multi agent system based adaptive relay setting strategy is proposed to define the optimal relay settings...
This paper presents a new algorithm for fault detection, classification and location which compensate for phase angle error due to line charging current using synchronised phasor measurements in SMART GRID. The paper includes fault detection with combination of phase and sequence components by using ground distance relay expression in terms of sending and receiving end voltages and currents. Here...
Power grid advances in the last years allowed new distributed applications developments. In this context, time synchronization is a very important issue, as many applications need to achieve high synchronization accuracy. The IEEE 1588-2008 standard [2] defines the second version of PTP, designed to achieve clock accuracy in the sub-microsecond range. In these scenarios Ethernet network redundancy...
With the rise of process automation in distribution power systems an automated disturbance management becomes possible. Whereas many techniques for outage-free service restoration exist, they are however specially customized for target grids and rely on fault circuit indicators to isolate the fault location. For service restoration schemes to become more flexible a standardized grid topology model...
The goal of this paper is to demonstrate the feasibility of a commercial protective relay having its setting changed automatically and in real-time. To demonstrate this, a closed loop test rig with the Real-time Digital Simulator (RTDS) and a commercial protective relay was set. The RTDS gives the opportunity to automatically set real-time different protection functions and settings of a commercial...
In recent years, an increasing number of fault detection devices based on the traveling wave principle have been developed and used in the power system. The parameters of each component in the power system should be analysed in depth to find out their influence on the fault traveling wave. In this paper, the influence of the overhead line physical parameters on the fault traveling wave is mainly analysed...
This paper presents the functional requirements for SCADA system for effective utilization of features provided by IEC 61850, IEC 61850 compliant protection & control Intelligent Electronic Devices (IED), network switches and other substation automation components. Currently numerous substations in the world are implemented with IEC 61850 edition 1 standard based substation automation systems...
Development of standardised solutions utilising new technologies at the utility level is a vital part of the integration process of those technologies. This paper will cover the development of transmission level protection schemes which utilise ‘self-monitoring’ algorithms to adapt the relay protection in response to failure of protection scheme components. The advent of enhanced communications bandwidth...
The power distribution grid of a DC data center is unique due to the highly capacitive characteristics of both the output of the DC power source (Uninterruptable Power Supply — UPS) and the input of the distributed load (multiple Power Supply Units — PSU). In case of a short-circuit to ground in such a system, oscillations are observed due to discharge of the capacitors through distributed RL network...
Comprehensive testing of a bus bar protection system during commissioning or factory acceptance tests has always been a quite challenging and exhaustive task. Using a dynamic simulation software which directly controls multiple conventional test sets for simultaneous injection of test currents into all bay units is very efficient, since it does not require any rewiring all the time. Within the software...
Based on the fault characteristics of wind power system, the adaptability of traditional directional relays is analysed systematically in this paper. Firstly, the fault characteristics of wind power system are given briefly. Then the operation performance of directional relays in power systems with wind farms is analysed by the fault characteristics of wind power system. Eventually, the analysis results...
In this paper, a new frequency estimation algorithm based on the DFT (Discrete Fourier Transform) is proposed to increase the estimation accuracy. The proposed algorithm consists of three stages such as DFT, frequency estimation and error compensation, and iterative loop. First, the input voltage signal is decomposed into two components by using DFT. Secondly, the two components, the real part and...
Areas with only one connection to the transmission system are vulnerable to unintended blackouts after a failure. This paper describes two case studies. An area on the west coast of Norway has several large generators with frequency control capability to support the network. A challenge in this area has been to ensure continuous operation in case of switchover to island operation. The second involves...
Inverse time overcurrent relays are widely used for the protection of distribution networks. They detect the current caused by a short circuit fault and after an appropriate time delay disconnect the faulted item of plant from the network. Many electrical faults, especially those occurring on underground cables, are intermittent in nature and are commonly referred to as “pecking” faults. Such faults...
This paper proposes a novel methodology to obtain the high frequency transfer characteristics of a three phase power transformer using two-port Vector Network Analyzer (VNA), which has been widely used in the high frequency RF electronic circuit. For a 50kVA rated three phase power transformer, fifteen measurements using two-port VNA were conducted to assemble a six by six S-parameters of the transformer,...
Secure operation of distance relays is of utmost importance to ensure the integrity of a power system. Mal-operation of distance relay's unblocking function during power swing is possible in case of transmission lines along the same right of way. An attempt is made in this paper to make the distance relay robust by utilising the available synchronised measurements. A differential active power approach...
The testing of protection and control devices and schemes in energized substation is always a difficult task that requires careful execution while ensuring the test object is properly isolated from the rest of the substation equipment. This paper introduces the methods and tools defined in IEC 61850 Edition 2 that support the virtual isolation of the tested functions in a live substation and then...
In this paper, we presented a computational modeling of frequency relay for islanding detection of distributed generation (DG) by the performance of frequency estimation methods. For this end, are presented an analysis and application of four methods of fundamental frequency estimation applied in distribution systems with DG in islanding situation such as: (a) Zero crossing, (b) adjustment of points...
Protection system is an indispensable part of power network to keep power components secure and reliable. Protective relay testing become more and more important when many new protection algorithms emerge owing to the development of new technologies. In this paper, a hardware-in-the-loop real time simulation platform is developed based on Opal-RT's eMEGAsim simulator and ABB Relion relays. Data exchange...
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