The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper presents an algorithm for determining fault section on Modular Multilevel Converter (MMC) based hybrid High Voltage DC (HVDC) transmission system. The hybrid transmission system consists of an overhead line followed by a subsea cable for deep-water oil and gas processing. The algorithm is based upon independent analysis of post fault characteristic signals at each terminal. These characteristic...
In this paper, a multi-degree open-circuit faults diagnostic algorithm, for improving condition monitoring ability of spacecraft solar cell system, has been proposed. This algorithm combines the output parameter, output voltage, output current and the impedance of solar cell system under low frequency domain. The algorithm can be used to diagnose the degree of faults quantitively and quickly. The...
This paper presents a protection scheme for a medium voltage dc (MVDC) link, that meshes three different MVAC distribution grids through ac/dc power converters. The proposed scheme includes active current limiters, hybrid circuit breakers and a communication layer for the coordination of these protection devices and power converters (logic selectivity). Active current limiters, installed just after...
This paper analyzes the unbalance problem of a standalone cascaded doubly-fed induction generator feeding unbalanced three-phase load. Under this working condition, the output voltages become un-balanced and give rise to a negative sequence component. The classic vector control strategy does not provide the desired performance. A compensation method is proposed to balance the stator voltages. The...
Short-circuit detection is one important feature of a gate-drive unit and a solution without a collector sense is preferable. With monitoring the gate-emitter voltage, a short can be easily detected. A circuit, which detects and turns off the short, and measurements for different shorts on high-voltage IGBTs are presented.
Paper presents performance of the 40kVA autonomous, adjustable speed generation system in a short-circuit condition, protected by a B-class tripping switch. Tripping switch is unable to clear the short-circuit event when an inverter current is limited, thus a topology of asynchronous bypass is developed, which delivers additional current directly from permanent magnet generator. Experiments of the...
Recently introduced Bi-directional Z-Source breakers [1] are capable of clearing the short circuit fault within a few microseconds. In this paper, various applications and protection requirements for Bidirectional Z-Source breakers are discussed. Detailed comparison between de-rated AC breakers and Z-Source breakers is discussed. Breaker design criteria are explained with the help of simulation results...
The paper addresses the problem of fault detection in an unbalanced microgrid with distributed generators, using algorithms based on harmonic estimation: Wavelet Transform (WT), Fast Fourier Transform (FFT) and Reduced Fast Fourier Transform (RFFT). Simulations were carried out in the MATLAB/SimPowerSystems environment. Modified IEEE13 bus system with distributed generation was used. Experimental...
Fault-tolerant multilevel inverters outperform known fault-tolerant 2-level inverters regarding efficiency and power density. The most promising fault-tolerant multilevel inverters for system voltages below 2 kV are the flying capacitor and the active neutral point clamped type. They differ regarding required voltage overrating of semiconductors, tolerance for open and short-on failure types and maximum...
The paper examines application of wavelet transform for voltage dips detection in microgrids with distributed generation. IEEE13 test grid with added 1.6 MW distribution generators is used for evaluation. Distribution generators are two 0.8 MW doubly-fed induction generators. Matlab/Simulink environment is used for modelling and evaluation of proposed algorithm for voltage dips detection. Six types...
The Z-Source circuit breaker is a type of DC power electronic circuit breaker, which is able to autonomously isolate faults. It uses a circuit of passive components to autonomously commutate the main conducting switch (a thyristor) off during a fault. In order for the ZCB to operate correctly, the thyristor must remain reverse-biased for a defined time period when a fault occurs, i.e., the minimum...
This paper discusses the stator winding interturn short fault detection for three phase Permanent Magnet Synchronous Machines (PMSMs). The implementation of the Extended Kalman filter (EKF)-based fault detection algorithm is discussed. The implemented algorithm was verified with the emulated fault during different operating conditions of the drive. Measurements on a real PMSM and the implementation...
This paper introduces the fault behavior of full bridge modular multilevel converters (MMCs) considering a non-simultaneous blocking of the two half bridges in each sub-module. In order to protect IGBTs in the full bridge sub-module, both sides of a full bridge sub-module are not blocked at same time point. It is assumed that the first blocking of both sides is random in each sub-module, so there...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.