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Locating high-resistance grounding faults poses a tough and challenging problem for the safety of DC railway systems. High-resistance grounding fault current isn't sufficient to trigger switches, which may expand the accident or turn into potential hazards. In order to overcome the limits of the existing methods (such as signal injecting method, resistance method and so), developing a novel fault...
Since IEC 61850 became the widely used standard for substation communication with a lot of implementations. Testing is an important issue. The standard in its current version covers some possibilities and approaches for testing in general and for measures of performance. Nevertheless some issues came out which needed to be clarified with the new edition of the standard. Edition 2 will be available...
The paper describes the concept of synchrophasors and the introduction of synchrophasors for protection applications in IEEE PC37.118.1 and then discusses different substation and transmission line protection applications. Requirements for reporting rate, time synchronization and communications architecture are discussed. Testing of protection systems based on PMUs is described at the end of the paper.
Fuse-saving practices have coordination limitations at higher current levels — it is common for the upline device to trip and the fuse to operate at the same time. The result is frequent momentary outages for many customers and blown fuses, even for temporary faults. These challenges have led some utilities to abandon the practice of fuse-saving and instead migrate to a fuse-blowing philosophy. The...
Busbar protection is described for a bus with current inputs for up to 32 bays. For busbar protection with IEDs and MUs using IEC61850–9–2 process bus, communication traffic jams are the main concern, due to transferring 80 samples/cycle data from all bay MUs to IED via 100BASE-FX. This paper describes peer-to-peer connection between MUs and IED in order to segrigate the SV messages of 32 bays on...
This paper describes how increased functionality of the Network Rail Integrated Protection and Control (IPC) extended IEC 61850 station bus solution unlocks the ability to rationalise the electrification system design, and hence achieve a substantial reduction in primary plant requirements when delivering the new railway electrification schemes committed by the Government.
Distribution system operator (DSO) sometimes needs to operate the large network which means operating of the network with big capacitive current (in Czech Republic more than 800A). This operation puts the emphasis not only on the setting of the earth fault relays but on the safety of the point of fault too. The paper describes the theoretical analysis, simulation and tests in real compensated distribution...
On distribution systems similar to that shown in Figure 1, in the event of a single phase to earth fault, the source protection will trip on earth fault. After the source has cleared, an unearthed network is left, backfed via the primary substation. Other than a very low level charging current, no fault current will flow. UK Power Networks detect this by neutral voltage displacement (NVD). Where a...
Due to its current limitation, Inverter-interfaced Distributed Generation (IIDG) is supposed to have little impact on protection system of distribution networks. However, in case of high power IIDG, the situation could be changed. This paper aims to show situations in which IIDG could provoke false tripping to overcurrent protections along distribution feeders. Proposed solution is to provide directional...
Effective voltage control is essential for the satisfactory operation of distribution networks. The increased connection of distributed generation to existing distribution networks challenges the current methods of controlling network voltages. Network voltage is primarily controlled by changing tap position of the primary transformers. The transformer secondary voltage will be automatically increased...
At present, gas protection and current differential protection are generally used as the main protection for traction transformer in China high-speed railway. Overcurrent protection with busbar low-voltage start-up is used as the backup protection installed at HV side and LV side of transformer. This paper introduces the principle of overcurrent protection with busbar low-voltage start-up, and then...
To feed electric train, the structure of traction power supply system is very different from utility grid. The single-phase traction loads result in some problems, such as negative sequence, harmonics, reactive power and crossing neutral sections. Based on the existing traction power supply system, the active power filter is used to construct cophase traction power supply system. It not only eliminates...
IEC 61850 is the new standard for communications in substations that defines a new generation of protection applications based on high speed peer-to-peer communications between different substation devices. Accelerated protection schemes use permissive or blocking signals exchanged between relays at the two or more ends of the protected transmission line in order to provide fast fault clearing for...
The requirements for improvements in the efficiency and quality of protection schemes at the transmission and distribution level of the electric power systems highlights the need for development of new methods and tools that can help the industry achieve these goals. The paper describes an object-oriented engineering process for the development and implementation of protection schemes, the IEC 61850...
This paper reviews the characteristics of inrush current and analyses its causes. The development of digital substation and the concept of integrated protection are also outlined. The paper studies different models to simulate several kinds of inrush and internal short-circuit fault. Through these models, the new composite algorithm is analysed in order to verify the reliability and sensitivity of...
The digital substation and the implementation of IEC61850 are fundamental to the future of protection relays. The IEC61850 standard, "Communication Networks and Systems in Substation", provides the basis for the communication system for the digital sub-station's protection and control schemes. Section 9–2 defines the Ethernet based communication network providing data transfer between primary...
In this paper the authors report current experience of IEC 61850 application in the Portuguese transmission system through the presentation of the Ermesinde case study. Adopted physical and logical architectures, function allocation, as well as engineering tools and processes are described and discussed. In the second part of the paper a future outlook for advanced transmission system automation is...
This paper provides an overview of recent developments in high availability networks and new redundancy protocols designed to guarantee seamless failover and proper functioning of the most critical substation automation applications such as tripping via GOOSE (Generic Object Oriented Substation Event) messages and IEC 61850 Process Bus based on switched Ethernet. The authors describe most common redundancy...
Transmission level protection functions are increasingly being looked at for Distribution systems. This can be attributed mainly to the enhancements being planned for by the Operating Companies, to increase the system efficiency, and also to ensure reliable power supply to the end Consumers. Slowly, the catch word "Smart Grid" is being consciously and progressively transformed to practical...
The advent of IEC61850 Standard has ushered a new age for substation automation. This standard has gained a very strong footing in Europe and its application is spreading across the world. In USA the progress towards IEC61850 implementation is relatively slower. IEC61850 holds great promises for substation automation and protection. There are many advantages that this standard brings to the area of...
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