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The development of a reliable and effective protection system is one of the greatest challenges in the realization of the multi-terminal HVDC (MTHVDC). This paper proposes a communication-less fault detection strategy based on travelling waves which is used in a MTHVDC which is integrating an offshore wind farm. The algorithm relies on using the discrete wavelet transform of dc current measurements...
This paper presents a protection scheme for multi-terminal Voltage Source Converter (VSC)-based HVDC systems, designed to detect and clear cable-to-ground faults in a range from very low to relatively high impedance. The protection scheme consists of two complementary and integrated layers: a protection layer for low impedance faults without communication between the terminals and a slower layer for...
Due to the increasing complexity of our electrical power systems, more complex protection schemes are used to protect transmission lines, transformers and other equipment. Simple conventional protection testing using a single test set for injection of steady-state voltages and currents is not suitable to verify the correct behaviour of such advanced schemes. Additionally the potential problems of...
The system integrity and reliability is a major task of transmission system operators (TSOs). Different tools are available to drive a secure power system. But most of them missed the assessment of the influences of protection systems on the system security. Therefore we introduced the Dynamic Protection Security Assessment (DPSA). Protection systems like distance protection relays were included in...
This paper describes a solution of a protection algorithm intended to detect internal element failures for large capacitor and filter banks. For such banks typically H configuration is used. Different fuse arrangements are also discussed. The basic concept is to detect and record the number of failed elements; to identify the failure locations; to alarm failures to the supervisory system and finally...
Recently, the application of general communications services, such as Ethernet, for communication routes for protection purposes has been attracting attention. The approach is similar to that for other power system communication services and it is anticipated that it will result in a reduction in total system costs, including that of the communication infrastructure itself. A number of utilities have...
Decarbonisation of the electricity industry using wind generation along with uncertainties in generation and demand profiles are some of the factors that have led to highly variable transfers across National Grid's critical transmission boundaries. Safe, secure and efficient operation of the transmission system relies on increased utilisation of existing transmission capacity and it is managed by...
Network switches for digital substations are normally offered with switching capacity (e.g., 48 Gbps) and interface options as Fast (100 Mbps) or Gigabit (1000 Mbps) Ethernet ports, but it is still obscure how to relate such features with the performance requirements for power utility applications. Many management flow control functions are also offered, such as QoS, CoS, VLAN and so on, but how these...
This paper investigates implementation of a new protection named Longitudinal Tapped Admittance (LTA) transformer protection. A brief introduction of LTA is given at first. Then the selection of phasor filter for voltage and current phasors is discussed based on the trade-off between calculation speed and security. As three-phase transformers normally uses star-delta connection, the arithmetic to...
This paper describes a new algorithm for selection of faulty circuit in parallel series-compensated lines. It suits for protection of such lines and uses one-end phase currents measurements only. The developed method has been tested and evaluated using signals obtained from versatile computer simulations. A detailed models of considered transmission line including the SC&MOV banks as well as the...
The introduction of the RIIO-T1 price control in 2013 brought a significant increase in the scale of construction works in the SP Transmission area. This includes modernisation of end of life assets and extensive reinforcement to accommodate significant volumes of renewable generation. In order to meet the demands of project throughput, a need to create efficiencies in the design and delivery of Protection...
The successful implementation of a restoration strategy after a wide area blackout is an integral part of the electrical service security our industrialised civilisation relies on. Incorrect reactions of protection relays can force this time critical procedure to be restarted again, lowering its overall probability of success. This paper states the basic principles of power system restoration focussed...
Line Current Differential Protection is an increasingly important protection scheme due to the fast and absolutely selective detection of faults. The essential part of the Line Current Differential Protection, also known as 87L protection according to ANSI/IEEE C37.2-2008, is the communication and the related time synchronization for synchronous sampling. A widespread and well established technology...
This paper shows the experience of Araz Energy using a Process Bus Solution in four 110 KV (as retrofitted projects) Substations in Azerbaijan. Araz Energy proposal to BEG (Baku Electric Grid that is locally called “Baki Elektrik Shabakasi/ BES”) was based on the Hard Fiber Process Bus system made by General Electric-Multilin (as part of General Electric Digital Energy). The use of the Process Bus...
The fault protection is a critical element to ensure the reliable and secure operation of DC distribution systems. Most DC distribution systems are tightly coupled systems with low line impedances which may result in fast current increase during a fault. Thus, it is challenging to develop a fast and reliable DC fault protection method. This paper proposes and develops a novel fault inductance based...
The rise of distributed generation units especially in low and medium voltage grids leads to a demand for more sophisticated protection and control schemes. Since dedicated protection systems as used in high voltage levels are too costly for a wide-spread usage in medium and low voltage levels, a centralisation of protection functionality may be a promising solution. However, with traditional type...
Post-fault oscillations have recently been identified as being one of the main causes of maloperations of earth-fault protection in compensated MV-networks [1]. Until now, the theory regarding post-fault oscillation condition has been missing from ‘classical’ earth-fault protection analysis, e.g. [2], where only healthy-state, inside and outside fault conditions have been considered. This paper adds...
One of the aims of the “Postes Intelligents” project is to design, test and commission a protection and control system using IEC 61850 process bus both for the data acquisition of the protection functions and for tripping. This paper describes the findings and the experience feedback of tests of complete digital functional chains of distance- and differential line protection. The test set includes...
In the paper two classes of algorithms for ground fault detection in power networks are described and their sensitivity is evaluated. The algorithms considered are based on admittance (conductance, susceptance) measurement as well as watt/var-metric approach with active/reactive current measurement. The impact of network compensation level on the admittance relay performance is also studied.
This paper discusses SSCB (Solid State Circuit Breaker) based DC shipboard distribution system protection in different perspectives. Unique features of DC distribution faults are analyzed and corresponding protection requirements are discussed. Latest SSCB technologies are presented and suitability for DC shipboard power systems is addressed. An overall evaluation gives out advantages and disadvantages...
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