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The impact of wind generation on high frequency, transient-based overhead line protection is investigated. An 8 bus section of the 132kV Scottish network with a realistic DFIG-based wind farm model is simulated on a real time digital simulator. Short circuit studies are conducted on a double circuit overhead line adjacent to the wind farm. Three case studies are compared: the DFIG model, a model with...
Line current differential protection creates challenges for relay design and application. From a design perspective, the distributed nature of the line current differential system imposes limits on the amount of data that can be exchanged between the system terminals and calls for data alignment schemes to enable the differential protection principle.
In the paper, the complete lightning model for HVDC transmission lines is presented, and the model is divided into five parts: lightning discharging model, insulator string flashover model, arrester model, tower model and conductor/ground wires model. The proposed lightning model was successfully tested in the PSCAD/EMTDC software. And the model is shown to be a potential tool for studying on lightning...
This paper presents results of statistical analysis of criteria signals that can be used for power transformer inrush discrimination. All criteria signals have been defined and evaluated on basis of simulative studies of numerous transformer normal and abnormal operating conditions. For all criteria signals the respective operation thresholds are also recommended. Simulation data has been obtained...
Repetitive transient aging is not a well understood phenomena in the high voltage world. For this reason, an aging waveform has been designed to understand what the scale of the impact of these pulses is on the paper insulation of a transformer. The times to breakdown between AC plus transients and clean AC are analysed and a clear trend is identified showing that transients are damaging to the insulation...
This paper describes an approach/philosophy that can be adopted when applying Intelligent Electronic Device (IED) based Protection and Control (P&C) Solutions to Non-Standard substation topology - the approach aims at reducing P&C costs and risks associated with application design errors.
This paper mainly study on the model predictive control (MPC) based method in the emergency voltage control. The coordinated voltage control scheme and the MPC model of voltage control are introduced firstly. Next, the Lagrange decomposition and auxiliary problem principle is employed into the MPC model of voltage control and a distributed MPC based voltage control scheme can be obtained, by which...
A major challenge facing utilities today is the successful configuration and testing of multi-vendor protection schemes using the IEC 61850 standard. Even though the IEC 61850 standard allows for interoperability between different manufacturers' relays, the implementation of the communication protocol varies greatly from vendor to vendor. The standard does not mention how the IED should be configured...
Distributed generation is increasingly likely to play a major role in electricity supply systems as recognition is made of its low carbon credentials. However, the integration of these units at distribution voltages is a major challenge for utilities. One particular issue is that generators may, unintentionally, continue to supply local demand when areas of the network are isolated from the main system...
In the paper a new method of high resistance fault detection meant for current differential protections of two-terminal transmission lines is presented. The method is based upon calculation of line differential admittance in pre-fault and in faulty conditions. As the ground fault current during high resistance faults is comparable and, sometimes for long transmission lines, even lower than the line...
The application of numerical busbar protection technology is lagged behind that of other protection functions, although static technologies is still usual for busbar protection but the latest numerical technology provides security, dependability and much grater range of facilities.
UHV/EHV long transmission lines have large distributed capacitance and shunt reactors, which may have significant effects on the operation of a traditional distance relay. The distance relay without considering any of the above two factors will operate with serious overreaching or underreaching. Several papers have analysed these effects on the measuring impedance of distance relay and proposes different...
In terms of cost reduction and productivity improvement, the protection, automation and control systems of Portuguese Distribution Substations have experienced major developments during the last three decades. Those changes aimed to increase the quality of service, financial performance, flexibility, reliability and more capacity to monitor and control all the primary equipments of a substation. The...
The introduction of a process bus connection was one of the features that have been added by IEC 61850. Yet - implementations of process bus are non existent in substations supporting IEC 61850 today. One of the hurdles so far was the requirement for accurate time synchronization. Introducing IEEE 1588 finally provides the technology to solve that issue in a smart way by using the communication network...
With the increasing demand for connecting cleaner energy generation from distributed renewable energy resources and new nuclear power stations, the future transmission network in the UK is expected to require increasingly more active primary technologies such as HVDC connections and FACTS equipment. These devices will enable the optimum use of the power transfer capability of the existing transmission...
This paper proposes a centralised Loss of Mains (LOM) detection technique to be implemented with a new network management system (NMS), the AuRA-NMS, an autonomous regional active network management system currently being developed in the UK through a partnership between several UK universities, two distribution network operators (DNO) and ABB [5].
This paper describes how dynamic line rating (DLR) is applied for load management and protection in two applications to enable a larger penetration of wind generation. One application is installed by Central Networks on a 132kV double-circuit line between Skegness and Boston (North East of England). Another application of the DLR approach is installed by Northern Ireland Electricity (NIE) on the Omagh...
In this paper, we first review the need for communications-based protection of subtransmission lines and show the advantages of directional comparison protection using spread-spectrum radio channels for this application. After a brief description of the applications of directional comparison protection over radio channels in Mexico, we provide data on the field performance of protection schemes and...
National Grid has been installing Numerical Busbar Protection (BBP) systems at its 400kV, 275kV and 132kV double busbar substations for approximately ten years. This Paper investigates the design, operational and lifetime management experiences/challenges associated with moving to these solutions. The paper will consider these challenges under the following five categories:- ▪ Policy and application...
This paper will focus on the IEC 61850 process bus architecture design for a mesh corner transformer bay within National Grid. A range of architectures can be applied, depending on the requirements for each substation such as reliability, availability and cost. Different possible architectures for the bay are designed. The system reliability and availability figures are estimated for each architecture...
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