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A large body of research is currently being conducted into superconducting power system applications, targeting improved efficiency and reductions in system size and weight. In order to attain the required levels of safety and reliability of the superconducting power system, effective protection systems, tailored to the specific fault behaviour of the novel components must also be in place. This paper...
A hybrid relay scheme, which combines the advantages of a quadrilateral impedance relay and a travelling wave fault locator for fault location on a mixed overhead and underground transmission feeder, is described in this paper. A redesigned quadrilateral impedance relay has the ability to determine the fault section and displays good performance to resist the influence of fault resistance on fault...
Communication is a key factor to the success of the future Smart Grid. Among various technologies, Ethernet is a predominant one for Local Area Network (LAN) communication due to its low cost and high speed and Power Substations will see increasing use of Ethernet in the protection & control sector. The Ethernet based IEEE 1588-2008 time synchronization protocol can realize sub-micro second accuracy...
Development of a microgrid (MG) system brings some emerging challenges. One of them is the fault protection system. In order to develop an optimal fault protection algorithm, this paper surveys dynamic and transient behaviours with respect to two operation modes of a microgrid, namely, islanded and grid-connected modes. Modelling and simulation of the MG's operation are performed by the PSCAD/EMTDC...
This paper is focused on locating earth fault by means of short-term additional earthing of unaffected (healthy) phase and the determination of fault distance based on the distance protection principle. The functionality of above mentioned method was verified during experiments, which were performed in the actual distribution network. The results of the experiments showed that the method of additional...
A novel single-ended traveling wave fault location method applicable to the distribution network with multiple branches is presented in this paper. The method only depends on the arrival times of the initial aerial-mode and zero-mode travelling wave, and it is not affected by structure of a distribution system itself. Therefore, good results can be achieved for precise fault locating in multi-source...
The assessment of critical system states via intensive power system simulation is more and more common especially for stability studies. The Dynamic Security Assessment (DSA) is one way to investigate the stability of a power system by simulating different contingencies. But one is mostly missing, the models for secondary equipment. To integrate protection systems in the simulation environment, the...
A novel protection scheme for two-phase faults in power distribution system with neutral ungrounded is presented. The feasibility of tripping single-phase circuit when a phase-tophase or two-phase-to-ground fault occurs is studied with induction motor loads as the focus. The paper at first analyses the effect of a induction motor runs with one phase cut off theoretically. And then a real power distribution...
Distribution networks must be equipped for a significant increase in future electrical demand. This challenge must be met in a cost-effective manner and without undue environmental impact. This paper quantifies the operational benefits of the Capacity to Customers (C2C) project presently being led by Electricity North West Limited in the UK. The objective of the project is to use demand-side response...
IEC 61850 is the standard widely used for power utility communication utilizing GOOSE for real time communication as well as Client/Server for SCADA communication. Factory acceptance testing (FAT) and site acceptance testing are described in the standard in general manner. This paper describes practical experiences when putting into operation substations according to IEC 61850. Since functional testing...
Faults on overhead power lines cause transients that travel at the speed of light and propagate along the line as traveling waves (TWs). This paper presents a new algorithm for TW fault locating suitable for implementation in line current differential relays. The paper presents the new algorithm in detail, including filtering, phase and mode selection, time stamping, and compensation for dispersion...
The signal of travelling wave has the merit of immunity to system oscillation, transition resistance, CT saturation and the neutral point operation modes; it has been widely applied in field of fault detection and protection. Especially in isolated neutral grounded wind farm distribution network, the algorithm using multiple-bay travelling wave's information can exclusively achieve the fast fault...
Because the market regulation in Brazil, power transmission companies are paid for the availability of their lines. When a fault occurs and the line becomes unavailable, such companies are penalized for the time the line is off service. Thus, fault location systems that can reach higher accuracy to estimate the fault location minimize the downtime of the line and, therefore, the application of penalties...
At present High Voltage Direct Current (HVDC) Voltage Source Converters (VSC) are susceptible dc faults leading to extreme currents. The fault current cannot be controlled by the converter switching flows in the anti-parallel diodes. Protection devices are, therefore, required to operate with sufficient speed to avoid device failure. A method is introduced to calculate the critical time for protection...
This paper presents the recent progress in use the sampled measured values (SV) as described in IEC 61850-9-2 and IEC 61869. This protocol is used to replace the copper cabling for digital communication network in bringing the current and voltage measurement for protection and control substation systems. The technology is implemented through equipment called merging unit, which digitizes the analogue...
This paper presents a critical evaluation of the combination of the wavelet transform and neural network techniques into high voltage transmission line protection. These techniques are used to enhance the ability to discriminate between different types of fault at any point of the protected line, relying on only single-ended measurement of the induced transient information of the fault. The main objective...
The rate of change of frequency during transmission system disturbances in UK will increase in incoming years. This is due the decreasing system inertia and increasing maximum generation loss in the system. Therefore, ROCOF protection will require higher setting to prevent unwanted operation while still ensuring correct detection of LOM condition. This paper proposes risk assessment analysis as a...
The zero-sequence mutual inductance between parallel transmission lines can weaken the reliability of protective relay. As a novel zero-sequence directional element is proposed based on the model recognition theory, an inductance model is established for the internal fault. The model error is small for an internal fault while large and oscillating for an external fault. To solve the problem on the...
In this paper, different methods to limit short circuit currents in DC traction networks are compared. Typically, DC traction networks are supplied by the AC grid by means of an uncontrolled diode bridge rectifier. In case of a low-impedance short circuit fault between catenary and rail, the fault current reaches a large value. For densely meshed networks the mechanical circuit breakers can become...
The increasing utilization of the mixed line requires more reliable technique to identify the fault section to overcome all the disadvantages of the existing schemes. Distance relay technique is not accurate and limited to one configuration of mixed line while the differential relay is more expensive since it requires more measurement hardware in the junction points and related communication channels...
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