New Ultra Fast Earthing Switch (UFES) device based on the vacuum switching principle

Lee

2021 IEEE Fourth International Conference on DC Microgrids (ICDCM)

et al. 2021

DC power supply systems utilising voltage source converters offer several advantages compared with their counterparts in marine low-voltage DC power distribution networks. In case of a two-level voltage source converter fed by a synchronous generator which is widely employed, a solid-state circuit breaker or a high-speed fuse is necessary for the converter protection due to its no fault-handling function and low fault withstand capability. However, the use of the solid-state circuit breaker and the high-speed fuse makes such a DC solution expensive and less reliable, respectively. Hence, this paper proposes a breakerless protection method for the voltage source converter-based marine DC power supply systems. The proposed method consists of an artificial short circuit on AC side (between the generator and the converter) and generator deexcitation. By employing the proposed method, the fault energy passing through the converter can be mitigated by the artificially generated short circuit between them and the current from the generator finally becomes zero by the deexcitation. This method allows for managing the fault energy under the converter and generator withstand capabilities without relying on the conventional breaking devices.

“…1). The ASC can be generated within 4 ms after the fault detection, considering commercially available fast earthing switches [6], [7].…”

Section: A Asc Methodsmentioning

confidence: 99%

Section: A Asc Methodsmentioning

confidence: 99%

Breakerless Protection for Voltage Source Converter-Based Marine DC Power Supply Systems

Lee

2021 IEEE Fourth International Conference on DC Microgrids (ICDCM)

et al. 2021

2016 18th European Conference on Power Electronics and Applications (EPE'16 ECCE Europe)

“…Conventional mechanical circuit breakers have closing times of more than 10 ms to establish a reliable current path, which is longer than the rise time to the first peak of the short circuit current [15]. Readily available mechanical switches used for ultra-fast earthing achieve closing times of less than 4 ms but can only be actuated once [16]. Ultra fast mechanical switches based on Thomson coil actuators (TCAs) have recently gained attention for applications in HVDC breakers.…”

Section: A LV Short Circuit (F1)mentioning

confidence: 99%

Protection of hybrid transformers in the distribution grid

Burkard

Biela

2016

Due to the increasing integration of renewable energy sources and power electronic loads into the distribution grid, a deterioration of the grid power quality is expected. Consisting of a low frequency transformer and a fractionally rated power electronic converter, the hybrid transformer can be applied to ensure a high power quality by controlling voltage, current, active and reactive power dynamically. For the application in grids with conventional grid protection infrastructure, hybrid transformers have to withstand considerable overvoltage and -current stresses during voltage surges or grid short circuits. Since the semiconductors are less robust than low frequency transformers with respect to these stresses, the effects of possible fault scenarios and a protection concept are studied in this paper. TABLE I: Specifications of the investigated 400 kVA, 20 kV-400 V HT. Parameter Value S n 400 kVA V MV , V LV 20 kV RMS , 400 V RMS , line to line Controllability ±10% of nominal V (LV side), P and Q S conv , V ser 40 kVA, 23 V Topology 2-level voltage source inverters, back to back DC-link 70 V, 5 mF, actively balanced split DC-link

IEEE Trans. Power Delivery

“…ES is designed to close very fast. Such ES are already commercially available under the name Ultra-Fast Earthing Switch (UFES) which closes in less than 1.5ms [34]. This switch is used to provide temporary bypass while the circuit breakers would take 1-2 cycles to establish permanent bypass to ground.…”

Section: B Sgicr Protectionmentioning

confidence: 99%

“…This is because SGICR enables ground fault detection by frequently closing neutral to ground. Once the fault is detected, the SGICR is bypassed within 1.5 ms using the device described in [34]. At the same time, the permanent bypass is triggered as described above in section C, restoring the neutral to a solidly grounded system.…”

Section: Duty Cycle and Frequency Parameters For Sgicrmentioning

confidence: 99%

Mitigation of Geomagnetically Induced Currents by Neutral Switching

Kovan

León

2015

This paper presents a novel mitigation technique to reduce the effects of Geomagnetically Induced Currents (GIC) on high voltage power systems. The method consists of connecting switching devices at the neutral grounding connection point of transformer banks. Only one transformer bank needs to be grounded through a switch to reduce GIC in a two terminal system. For multi-terminal systems, n-1 switches are necessary and the operation is independent from each other. The switching frequency and the duty cycle are selected from a tradeoff between the effectiveness of the method and the detection of fault currents. Transient simulations on a two bus 230/500 kV system show that the proposed switching at the neutral successfully mitigates the GIC. This proposed technique opens the door to a new family of GIC mitigation methods. Baris Kovan received the B.Sc. and the M.Sc. (Hons.) degrees in electrical engineering in 2008 and started pursuing the Ph.D. degree from Polytechnic School of Engineering of NYU, Brooklyn, NY in 2011.He works in the high voltage industry for power utilities as a consultant. His areas of interest are substation design, protection and control, transformer design, GIC, and renewable energy. Francisco de León (S'86-M'92-SM'02-F'15) received the B.Sc. and the M.Sc. (Hons.) degrees in electrical engineering from the National Polytechnic Institute, Mexico City, Mexico, in 1983 and 1986, respectively, and the Ph.D. degree in electrical engineering from the University of Toronto, Toronto, ON, Canada, in 1992.He has held several academic positions in Mexico and has worked for the Canadian electric industry. Currently, he is an Associate Professor at the Polytechnic School of Engineering of NYU, Brooklyn, NY. His research interests include the analysis of power phenomena under nonsinusoidal conditions, the transient and steadystate analyses of power systems, the thermal rating of cables and transformers, and the calculation of electromagnetic fields applied to machine design and modeling.Dr. de León is an Editor of the IEEE Transactions on Power Delivery and the IEEE Power Engineering Letters.