The dc distribution power system has drawn widespread attention and rapidly developed in recent years; however, its stability issue is one of the urgent challenges, requiring much attention. In previous studies, line impedance network often overlooked, which convenient for geographically centralized systems, but inaccurate distributed systems. this article, modeling criteria these two systems are simultaneously studied. For first, transfer functions from each input voltage or current...

It is well-known that the low-frequency negative input impedance of constant power load (CPL) major cause cascaded system instability, and heavier power, worse stability. In this article, a adaptive load-side parallel virtual (PALPVI) control strategy proposed to improve stability dc with buck-type CPL. First, adaptability derived followed up derivation corresponding compensation controller transfer function realize it virtually. Considering highly dependent on circuit parameters needs extra...

The stability analysis methods of single-bus dc distribution power systems (DPSs) have been widely studied; however, the multivoltage-level DPSs, which used in data center, all-electric ship, and so on, its are rarely reported. main focus this article is to study methods, especially impedance ratio DPSs. From point view whole system, two-port small-signal models DPSs established equivalent loop gains obtained judge system stability. On other hand, can be regarded as conventional at different...

Two individually stable converters are well-known preconditions for discussing the stability of a two-stage cascaded system. However, multistage system, relationship between its and subsystem is barely reported due to lack modeling method in-depth analysis. In this article, above problems solved. First, generic two-port small-signal model dc–dc established, equivalent minor loop gain calculated, which can be used assess system stability. On basis, condition triple-stage dc further deduced...

During the past decades, small-signal stability of interconnected converters has been extensively researched, and several impedance/admittance-based criteria were reported effectively verified. However, equivalence correlation among these have not clearly expounded. In this article, internal relationship existing five is first studied by modeling analysis for different converters, proving criteria. Then, from perspective application complexity, convenience system design, reliability against...

This paper presents a modified power supply system based on the current alternating (AC)-fed railways with neutral zones that can further improve eco-friendliness and smart level of railways. The complements existing infrastructure additional energy-storage-based electrical infrastructure. comprises electronic devices energy storage connected in parallel to both sides each zone traction substations, section posts, an management system. description functions such are outlined this paper....

AC heavy-haul trains produce a huge amount of regenerative braking energy when they run on long downhill sections. If this can be used by uphill in the same power supply section, reduction coal transportation cost and an improvement quality would result. To accurately predict consumption large slopes, single-particle model train dynamics was used. According to theory railway longitudinal section simplification, single based attributes, line conditions, running speed established. The applied...

To ensure that regenerative braking energy is fully utilized by traction trains in the whole railway power supply systems, an effective utilization scheme of based on regulation with a genetic algorithm (GA) proposed this paper. This consists conditioners (RPCs), transfer converters (ETCs) and central controller. A RPC connects two arms each TS, ETC section post (SP). The RPCs ETCs are controlled to distributed controller, which calculated GA. detailed calculation steps described. Moreover,...

In practical application, it is more expected that the impedance-based stability criteria can provide intuitive system design guidance. However, existing for complicated systems always aggregate all equipment/subsystem impedances. As a result, difficult to determine port impedance specification each should meet ensure and certain margin. this article, specifications of grid-connected dc distribution power are proposed. First, conditions presented based on dc-side subsystem ratio criterion....

This paper proposes a centralized-decentralized control strategy for regenerative braking energy utilization and power quality improvement in the modified AC-fed railway system with energy-storage-based smart electrical infrastructure. The proposal of can enhance ability to withstand rapidly recover from disruptions, thus providing further guarantees safe reliable operation conservation systems. First all, description are outlined, then principles implementation process centralized...

With respect to the problems of great impact on utility grid, increasing catenary voltage, limited utilization rate regenerative braking energy (RBE) and irreducible cost electricity for locomotives caused by RBE generated electric whole railway line cannot be fully utilized in traction power supply systems. An management system (EMS) integrating electrical information is proposed this paper. A corresponding optimization algorithm also calculate distribution line. The structure working...

In order to effectively compensate negative sequence current (NSC) of the V/v traction system and reduce capacity cost railway power conditioner (RPC), a low-cost hybrid (HRPC) technology scheme considering regenerative braking energy is proposed in this paper. The HRPC consists an RPC with modular multilevel converter structure (MMC-RPC) static var compensator (RSVC). First, circuit topology principle NSC compensation are given. Then, configurations MMC-RPC RSVC presented active equipment...

Series arc fault is an important incentive for electrical fires. Wavelet transform a widely used series identification method. However, it difficult to distinguish the normal condition and when only using wavelet transform, large amount of redundant data will be generated. To solve this problem, paper presents new method which based on singular value decomposition. The experiment platform was built according UL1699, verified by experiments. presented in can well state. accuracy high, greatly reduced.

The dc distribution power system (DPS) has witnessed rapid development in recent years, and it is gradually characterized by multiple voltage levels, buses, converters. complex topology of the leads to some serious stability problems. Compared with cascaded DPS multiple-voltage-level paralleled buses outstanding advantage because higher efficiency case more buses. To study small-signal <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> a...

The impedance-based stability analysis methods for ac or dc electronic power systems are always separately reported. Even in hybrid ac–dc systems, few studies adopt both and criteria simultaneously, let alone discuss their correlation differences. In this article, the small-signal of grid-connected distribution is investigated at sides. First, by modeling system's input-to-output transfer functions, two equivalent-minor-loop-gain-based without right-half-plane (RHP) poles proposed,...

In a cascaded H-bridge rectifier (CHBR), the dc capacitor voltages need to be controlled balance by voltage controller when loads are unbalanced. However, will fail load unbalancing range exceeds certain limit under unity power factor; that is constrained AC and transmission of each H-bridge. First, relationships in CHBR were analyzed. Then, expression between was derived. Then limits maintain further deduced. addition, influence ripple total on investigated. Finally, an experimental...

Currently, the scale of dc distributed power systems (DPSs) keeps growing, which makes number buses larger and stability analysis more complex. In this paper, impedance admittance specifications multi-voltage-level DPS that restricts or bus-connected converters subsystems transfer function intermediate bus converter (IBC) is proposed studied. A two-voltage-level experiment platform constructed to verify specifications. It proved are able ensure DPS, thus guarantee designing process...

The stability region of multi-voltage level DC system is the bottleneck problem in analysis. Based on Brayton Moser mixed potential function theory, a simple three-stage cascade constructed, and unified simplified models under different control modes obtained. Then, according to theorem function, large signal criteria are proposed. Through further analysis, key parameters affecting obtained draw of. Finally, simulation results verify feasibility proposed criterion.

The DC side voltage stability is a prerequisite for the of cascade system with source converter (VSC). Compared small signal analysis method based on state space model, impedance model has simple modeling process and clear physical meaning. negative characteristic constant power load (CPL) will reduce effective damping system, resulting in instability. In this paper, two-port models VSC CPL are established respectively, strong grid weak evaluated ratio criterion. addition, influence...

Impedance-based methods are widely used and recognized for small-signal stability analysis of power-electronics-based power systems. However, the existing criteria complex systems always aggregate all equipment/subsystem impedances. As a result, it is difficult to determine impedance specification that each should meet ensure system certain margin. In this paper, method grid-connected dc distribution first proposed. Then, port converter proposed design. long as converters specifications,...

In this paper, a small signal model of independent photovoltaic-battery hybrid power system (PBHPS) is proposed. Based on the complete PBHPS, participation factor analysis conducted, and state variables highly correlated with DC voltage dominant mode are identified. On basis, keeping these variables, reduced-order deduced. Compared system, equates photovoltaic supply to constant source. It can reduce order matrix amount computation.

To ease the increasing electrical energy demand, reduce operation cost, and improve power quality of electrified railway, a low-cost scheme is proposed for recycling regenerative braking compensating negative sequence current (NSC). The hardware part this consists two three-winding transformers, railway conditioner (RPC), bidirectional DC-DC converter, an storage system (ESS), four sets thyristor-switched capacitors (TSCs) thyristor-controlled reactors (TCRs). In paper, firstly, structure...