Review of AC power theories under stationary and non‐stationary, clean and distorted conditions

Kukačka, Leoš; Kraus, Jan; Kolář, Milan; Dupuis, Pascal; Zissis, Georges

doi:10.1049/iet-gtd.2015.0713

Cited by 14 publications

(7 citation statements)

References 44 publications

(41 reference statements)

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“…Whether the apparent power of customer installation j can be accurately calculated plays a vital role in allocating CEL fairly. However, equation 15is not accurate enough to calculate the greatest possible apparent power absorbed by an unbalanced load [27,28], as the apparent power of the coupling effect between positive and negative sequence components should be calculated. More importantly, this partial energy arouses power or torque oscillation in inductive motors [7].…”

Section: Customer Emission Limit (Cel) Allocation Methods In Iec/tr 61mentioning

confidence: 99%

VU limit pre‐assessment for high‐speed railway considering a grid connection scheme

Chen

Tian

et al. 2019

IET Generation, Transmission & Distribution

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Single-phase 25-kV AC traction power supply systems (TPSSs) are widely used in high-speed railways (HSRs), leading to an increasingly prominent problem of voltage unbalance (VU) in the power grid. To fairly regulate the system VU level, implementing VU limit pre-assessment is an urgent need. A grid connection scheme, including traction transformer selection and exchange phase connection (EPC) design, is a vital part of TPSS design that obviously affects the voltage unbalance factor (VUF) of power systems. A uniform mathematical model is established using Thevenin's theorem, which reveals the impact of multiple grid connection schemes on the VU propagation behaviour of a three-phase grid. Afterwards, under the requirements of IEC/TR 61000-3-13, an improved VU limit pre-assessment process is proposed, which correlates mapping between the grid connection scheme and VU limit. The unbalance compensation calculation is given, adopting the allocation limit; furthermore, the optimal design of the grid connection scheme with minimized compensation capacity as an object is presented. The correctness of the model and the rationality of the pre-assessment process are verified by a case study.

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Section: Customer Emission Limit (Cel) Allocation Methods In Iec/tr 61mentioning

confidence: 99%

VU limit pre‐assessment for high‐speed railway considering a grid connection scheme

Chen

Tian

et al. 2019

IET Generation, Transmission & Distribution

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“…At the measuring point (PCC or bus) and under these conditions, the total apparent power of Buchholz S T is determined by Equation (9). In balanced systems, S has the same value as S T , while in unbalanced systems, S does not reflect the real apparent power of the system, and has a different value than S T .…”

Section: Of 17mentioning

confidence: 99%

“…At present, there is no theory agreed by the scientific community that allows to assess this type of phenomenon [9]. Most of the previous studies followed the expressions proposed in IEEE Std.…”

Section: Introductionmentioning

confidence: 99%

Compensation of Reactive Power and Unbalanced Power in Three-Phase Three-Wire Systems Connected to an Infinite Power Network

et al. 2019

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The compensation of an electrical system from passive compensators mainly focuses on linear systems where the consumption of charges does not vary significantly over time. In three-phase three-wire systems, when the network voltages are unbalanced, negative-sequence voltages and currents appear, which can significantly increase the total apparent power supplied by the network. This also increases the network losses. This paper presents a method for calculating the compensation of the positive-sequence reactive power and unbalanced powers caused by the negative-sequence line currents using reactive elements (coils and/or capacitors). The compensation is applied to three-phase three-wire linear systems with unbalanced voltages and loads, which are connected to an infinite power network. The method is independent of the load characteristics, where only the line-to-line voltages and line currents, at the point where compensation is desired, need to be known in advance. The solution obtained is optimal, and the system observed from the network behaves as one that only consumes the active power required by a load with a fully balanced current system. To understand the proposed method and demonstrate its validity, a case study of a three-phase three-wire linear system connected to an infinite power network with unbalanced voltages and currents is conducted.Appl. Sci. 2020, 10, 113 2 of 17 these inefficient powers. According to [13,14], imbalances at one point in the system can help offset some of the imbalances at another point. Such situations cannot be analyzed if only the modules of voltages and currents are known.The application of electronics, in the compensation of electrical systems, indicates that most industries today mainly focus on the use of active compensators. The advantages of these compensators or filters cannot be denied, especially for the compensation of non-linear systems. As compared to passive compensators, the active compensators are more expensive, less robust, and consume more energy. In certain situations, for linear systems, where the load does not vary with time, the use of passive compensators is a good alternative. They are configured from reactive elements (coils and/or capacitors). In this study, passive compensators are used to compensate for the reactive and unbalanced power resulting from the negative-sequence current of any three-wire system.The concept of compensation of an electrical system by passive compensators is not new. Steinmetz [15] developed a passive compensator to obtain a system of balanced line currents. He used a single-phase load with known data, and compensated it with a coil and capacitor and we believe that the voltages in the study were balanced. This study has been extended by many authors [16][17][18][19][20][21][22][23][24].Gyugyi et al.[25] studied compensation through passive compensators for a three-wire linear system with unbalanced load and balanced voltages. For this purpose, they categorised the line currents into symmetric component values, and proposed...

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“…According to the research [28,29], there is some coupling power between the different components, not just the positive-sequence or negative-sequence power. Thus, the excited power calculation approach of load, based on the sequence component or vector method, could become invalid under the non-sinusoidal and asymmetrical conditions.…”

Section: Power Analysis Of the Proposed Hybrid Compensation Systemmentioning

confidence: 99%

“…Calculate the fundamental unbalance apparent power of the load and PFC using (28) Hysteresis current PWM method…”

Section: Control Block Of the Proposed Systemmentioning

confidence: 99%

Modeling and Control of a Novel Hybrid Power Quality Compensation System for 25-kV Electrified Railway

Chen

Wei

2019

Energies

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The severe power quality problems aroused by the single-phase 25-kV traction power supply system (TPSS), especially for the voltage unbalance (VU) and high-frequency harmonic resonance, have attracted increasing attention nowadays. In this paper, a novel hybrid power quality compensation system, including a power flow controller (PFC) and thyristor-controlled L and C-type filter (TCL-CTF), is proposed. The PFC can be used for VU compensation, and the TCL-CTF can be designed to filter out harmonics as well as compensate reactive power. Furthermore, an optimized compensation strategy is proposed, and the power quality of the TPSS can meet the requirements of the technology standard. Compared with the conventional scheme, the compensation capacity of the PFC can be reduced by 12%, as well as the cost. Finally, the effectiveness of the proposed system is verified by the simulation and experimental results.

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Review of AC power theories under stationary and non‐stationary, clean and distorted conditions

Cited by 14 publications

References 44 publications

VU limit pre‐assessment for high‐speed railway considering a grid connection scheme

VU limit pre‐assessment for high‐speed railway considering a grid connection scheme

Compensation of Reactive Power and Unbalanced Power in Three-Phase Three-Wire Systems Connected to an Infinite Power Network

Modeling and Control of a Novel Hybrid Power Quality Compensation System for 25-kV Electrified Railway

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