The dc impedance model of a modular multilevel converter (MMC) is the basis for analyzing harmonic resonances MMC-based systems. As an MMC typifies multiple response system, its internal dynamics and controls significantly influence external characteristics. In this paper, developed by transfer function method that considers typical MMCs. mainly include capacitor voltage fluctuation multi-harmonic characteristics, while consist control, positive-negative sequence separation-based phase...

High-frequency resonance (HFR) is a key issue of power electronics-based systems. Two solutions can be applied for addressing HFRs, including active damping method and passive method. For modular multilevel converters (MMCs), most the existing harmonic suppression methods are focused on methods, filtering virtual resistance. However, may lead to negative in its attenuation band resistance become high-frequency range when influenced by control delay. In order avoid effects delay increase MMCs...

Proton exchange membrane fuel cells (PEMFCs), recognized as promising sources of waste heat for space heating, domestic hot water supply, and industrial thermal applications, have garnered substantial interest owing to their environmentally benign operation high energy conversion efficiency. Since the uniformity oxygen diffusion toward catalytic layers critically governs electrochemical performance, this study establishes a three-dimensional, non-isothermal computational fluid dynamics (CFD)...

This paper proposes an accurate impedance model for line commutated converter (LCC) in the stationary frame. The commutation overlap process caused by transformer leakage inductance complicates modeling LCC. Traditional models are derived positive sequence and negative frame based on simplified process, which degrades accuracy limits description of frequency coupling. systematically analyzes effects model, with is established <i>dq</i>-frame. For clearly revealing coupling phenomenon LCC,...

This paper focused on a new type simulation platform. Restricted by the number of network nodes and time step, traditional all digital platform is not fast enough for modular multilevel converter Based HVDC (MMC-HVDC). presented real-time digital-analog hybrid including 49-level MMC, described method calculating proportion to original system. The characteristics were designed according dynamic response features actual system its was simulated analog devices. Depending special communication...

Hybrid high-voltage direct current (HVdc) system, which comprises a line-commutated converter (LCC) at rectifier side and voltage source (VSC) inverter side, is drawing wide attention due to its high reliability economic benefit. For such new transmission technology, the system characteristics are not comprehensively studied, inappropriate control parameters may be coherent instability. This article puts forward novel coherence analysis procedure that analyzes stability based on verified...

Isolated power systems (IPS) usually have multifaceted operational objectives in engineering scenarios, and many key tasks are performed by multiple pulsed loads. The research on multi-objective energy optimal scheduling isolated which contain loads is the subject of this paper. In addition, mobility maximum load performance value discussed. By introducing concept ship speed at end state, system maneuverability properly characterized final state speed, combined with efficiency loads, a...

Multi-infeed cascaded hybrid series-connected DC transmission technology combines the advantages of line commutated converters and voltage sourced converters. Hybrid is expected to play an important role in future power systems. It great importance understand system's behavior under steady transient states. This paper thoroughly examines responses different types faults. The benefits having such a system are also highlighted through fault analysis. In order cope with AC three-phase fault,...

The dc transformer (DCT) can be used to achieve a direct connection between various bus voltages. A multiwinding dual active bridge (DAB) structure is proposed in that occasion for dynamic simulation platform. For high voltage side, automatic balance and power-sharing achieved automatically without mandatory power sharing control. To deal with wide conversion gain application, multimode modulation peak current value optimization proposed. It has the tolerance short circuit operation under...

Partial discharge (PD) can indicate defects in HV XLPE cable accessories. A new land of split-core PD sensor is designed that be easy installed on-site and used safely, has a bandwidth from 3 MHz to 60 MHz. model accessory was made some typical phenomena this were simulated, such as sliding discharge, floating cavity discharge. tests find the features defects. The data analyzed spectra different types plotted using statistical parameters reveal feature patterns PD. been after sample testing...

Besides real-time numerical simulation technology, the laboratory-scale physical technology is an alternative for analysis and hardware testing of modular multilevel converter (MMC). It can realize full-scale connection with complicated control protection no need extra interface devices, which necessary in simulation. However, due to limitations on size investment, power loss rate MMC system inevitably higher than that real project, obviously will have a negative effect accuracy. To solve...

The Insulated Gate Bipolar Transistor(IGBT) life prediction is a technique that uses neural networks to predict the IGBT's remaining useful life(RUL). Past studies have discussed IGBT RUL under different situations, where models based on Recurrent Neural Network(RNN), Back Propagation(BP) Network, and other structures been widely used. With aging dataset provided by NASA PcOE research center, this paper introduces new approach stage. average accuracy of time-domain features 72.46%, one...

HVDC transmission has become the most valuable engineering technology because of its own advantages. But rapid detection and isolation DC side faults been one major technical matters in development grids. Highvoltage circuit breaker is an important equipment to solve this problem, becomes current research hotspot. According process breaker, paper analyzes fault limiting control breakers, proposes a method based on ROCOV (Rate Of Change Voltage) strategy operation arresters by sequence. It...

Bipolar VSC-HVDC scheme is one of the most feasible transmission technologies to integrate offshore wind energy source. While pole stops by suffering even a transient fault, other will block soon due overcurrent, then turbines trip which would cause critical impact on power system. A novel coordinating fault ride through strategy proposed solve problem here. First, operational behaviour DFIG under integration voltage regulation analysed; Second, based generation characteristics with...

For the heavy load urban power grid, short-circuit current is closed to breaking capacity of AC breaker. After voltage sourced converter high direct (VSC-HVDC) connected, VSC-HVDC will be provided during fault period, which cause exceed standard value and affect normal operation grid. Taking Xiamen project as an example, this paper analyses control mode, obtains calculation method. The / DC hybrid model built, correctness proposed method verified by simulation. results show that amplitude...