Search results for "Circuit breaker"
showing 10 items of 11 documents
SiC Based Latching Current Limiter for High Voltage Space Power Distribution Systems
2018
This study presents a novel Latching Current Limiter topology, based on a N-channel Silicon Carbide (SiC) MOSFET as the main switching element. The design has been carried out using only discrete components, without digital controllers. This design has been validated by simulation and with a prototype. Tests have been performed at 1000V, modifying the limitation times, current-limiting values and eventually checking the proper operation of the system.
A framework to determine maximum capacity of interconnecting DGs in distribution networks
2018
Interconnecting Distributed Generation (DG) in the distribution network is considered as an important area of power system planning. When the DG placed inappropriately, the DG can have negative impact on some important and critical characteristics of system performance such as increased power losses, degraded voltage profile, and mis-coordination between protection devices. This paper introduces a framework to determine the maximum capacity limits of interconnecting DG units in radial distribution networks in order to keep protection scheme unchanged, while the voltage profile remains within acceptable range and on the same time having the minimum power losses in the network; applying this …
Circuit Breakers – a legal analysis of volatility safeguards in the rules of stock exchanges on the occasion of the COVID-19 crisis
2020
Abstract This paper examines circuit breakers (CBs), i. e. emergency systems of trading venues that interrupt or restrain trading when significant price movements of financial instruments occur. After a description of the ratio legis and the economic fundamentals, the genesis and the different forms of CBs are presented. The European legal framework is then outlined. The relevant rules of the Frankfurt Stock Exchange (FWB) serve as an example.
Minimum Losses Reconfiguration of MV Distribution Networks through Local Control of Tie Switches
2002
This paper deals with the problem of optimal reconfiguration of radial distribution networks for minimum loss operation. The proposed control strategy of the open-closed status of the tie-switches is distributed, since every MV/LV node is provided with local controllers having some measured entities as input. It also does not prevent the system from the future implementation of centralized control; instead it may represent the first step toward a complete automation of the distribution system. The proposed strategy is indeed organized in hierarchic levels, the highest of which may be in the future a central control. After introducing the general problem of networks reconfiguration, a review…
Analysis of voltage dips propagation in MV distribution networks by using ATP-EMTP code
2003
In this paper, voltage dips simulation in electric power MV distribution networks by using an improved ATP circuit-breaker model are reported. An equivalent circuit of a MV distribution system is employed. The circuit-breaker is simulated by using a tool written in MODELS language and by arranging a time-variable differential arc-conductance based on the combination of Mayr's and Cassie's equations. The simulations carried out have shown how the amplitude of the voltage dips depends on the type and location of the fault and their duration is strictly related to the circuit-breaker parameters.
An Investigation of Protection Devices Coordination Effects on Distributed Generators Capacity in Radial Distribution Systems
2013
In the recent years, with the concept of Smart Grid, there are a great interest in integration of renewable energy based distributed generation (DG) units at distribution level. Along with a number of benefits, penetration of DG units in the distribution system imposes some serious challenges; protection requirements turns up as one of the most critical challenge in DG integration. In this paper the possibility and the potentiality of occurring mis-coordination between protection devices in radial distribution network is studied. The impacts of protection devices coordination on DG capacity are investigated. The penetration level, number, and location of interconnected DGs are used as param…
Control of solid-state fault current limiter for DG-integrated distribution systems
2017
Fault current limier (FCL) is a device that limits the system current under fault conditions without disconnecting the system and affecting the power system protection components such as circuit breakers. Many types of FCLs have been proposed to limit the magnitude of the fault current. Solid-state fault current limiters (SSFCLs) can limit the peak value of the fault current by applying several methods, such as controlling the system impedance or controlling the voltage that appears across the fault. In this paper, a new control scheme for the SSFCL circuit is presented. The control method is based on controlling the duty cycle of solid state switches to control the rms value of the system …
Transient DC-Arc Voltage Model in the Hybrid Switch of the DTT Fast Discharge Unit
2021
The focus of this work is the transient modelling of the DC-arc voltage on a Hybrid Switch (a mechanical switch in parallel with a static switch) of a key protection component called Fast Discharge Unit (FDU) in the Divertor Tokamak Test (DTT). The DTT facility is an experimental tokamak in advanced design and realization phase, which will be built in the ENEA Research Centre in Frascati (Italy). The FDU allows the safe discharge of the Toroidal Field (TF) superconducting magnets when a quench is detected or a failure occurs in the power supply or in the cryogenic system. In this work, the arc conductance of the mechanical By-Pass Switch (BPS) of the Hybrid Switch is modelled using the well…
Conceptual Design and Modeling of Fast Discharge Unit for Quench Protection of Superconducting Toroidal Field Magnets of DTT
2020
The paper deals with the modelling and simulation of a Fast Discharge Unit (FDU) for quench protection of the Toroidal Field (TF) magnets of the Divertor Tokamak Test, an experimental facility under design and construction in Frascati (Italy). The FDU is a safety key component that protects the superconducting magnets when a quench is detected through the fast extraction of the energy stored in superconducting magnets by adding in the TF magnets a dump (or discharge) resistor. In the paper, two different configurations of dump resistors (fixed and variable respectively) have been analysed and discussed. As a first result, it is possible to underline that the configuration with variable dump…
Transitions from grid-connected to island operation of Smart Microgrids
2019
In this paper a control methodology is presented to perform a bumpless transition from the on-grid to the offgrid of a smart microgrid. The derived controller manages the internal production in order to get to zero the tie-line active and reactive power flows so that the opening of the tie line breaker does not produce significant perturbations. Experimental tests performed on the microgrid built at the Polytechnic University of Bari demonstrated the effectiveness of the proposed control strategy.