Research on Theoretical Calculation Methods of Photovoltaic Power Short-Circuit Current and Influencing Factors of Its Fault Characteristics

Liu, Huiyuan; Xu, Kehan; Zhang, Zhe; Wei, Liu; Ao, Jianyong

doi:10.3390/en12020316

Cited by 16 publications

(27 citation statements)

References 20 publications

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“…In this approach, the differential equations are converted into algebraic equations at each time step h by implementation of implicit methods such as trapezoidal or backward differential formula (BDF). Using the trapezoidal method in this initial value problem, equation 30is reformulated as (31). Index n denotes the number of time steps.…”

Section: A Dae Solve Approachmentioning

confidence: 99%

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A General Mathematical Model for LVRT Capability Assessment of DER-Penetrated Distribution Networks

et al. 2020

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Low voltage ride through (LVRT) is one of the indispensable issues of recent decade in the context of grid codes. LVRT stands for the ability of a generation facility to stay connected during the voltage dip. Despite the numerous discussions in recent works, but they mostly concentrate on the LVRTbased control of distributed energy resources (DERs) integrated into a microgrid and its improvement. However, what has been hidden and not addressed any more yet is an index to measure the LVRT capability of a DER-penetrated distribution network (DPDN) under different voltage sags. This takes precedence when we want to evaluate the LVRT capability of DPDNs with consideration of various LVRT categories of DERs mandated in IEEE 1547 standard. This paper introduces a general framework for LVRT assessment of a DPDN by solving a system of differential algebraic equations (DAEs). Then expected LVRT capability of a DPDN is evaluated by a proposed LVRT index through the implementation of Monte Carlo simulation technique. INDEX TERMS Differential algebraic equation (DAE), Distributed energy resource (DER), Penetrated distribution network (DPDN), Low voltage ride through (LVRT), Monte Carlo

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Section: A Dae Solve Approachmentioning

confidence: 99%

“…Ref. [31] has proposed a theoretical method to calculate this fault current for the PV with consideration of its DC bus fluctuations to use in the LVRT assessment. Such calculations have to consider the network topology, its parameters and the type of faults that occur within the network.…”

Section: Introductionmentioning

confidence: 99%

A General Mathematical Model for LVRT Capability Assessment of DER-Penetrated Distribution Networks

et al. 2020

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“…Figure 2 shows a diagram of the vector decoupling control method. Under normal circumstances, the IIG operates under a unit power factor, and adopts the double loop control strategy with an outer voltage loop and an inner current loop [17].…”

Section: Control Strategy and Fault Characteristics Of The Iigmentioning

confidence: 99%

“…In the case of a fault, the IIG should possess a low-voltage ride through (LVRT) capability in order to meet the reactive power support requirements of the system. The reference values of the daxis and q-axis currents dref i and qref i are shown in Equation (5): Under normal circumstances, the IIG operates under a unit power factor, and adopts the double loop control strategy with an outer voltage loop and an inner current loop [17].…”

Section: Control Strategy and Fault Characteristics Of The Iigmentioning

confidence: 99%

An Improved Directional Relay Adapted to a Distribution Network with IIG Integration

Zhu

Wang

Zhao³

et al. 2019

Energies

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The integration of distributed generation (DG) into a distribution network changes the network's topology. Three-stage current protection for a radial distribution network cannot meet the requirements of relay protection for a distribution network with DG. A directional relay that is based on the positive sequence fault component (PSFC) can effectively identify faults in the positive and negative directions and can be used to solve the adaptability problem with three-stage current protection in a multi-source distribution network. However, DG and the traditional generators have different fault characteristics and are affected by different control strategies, which may lower the sensitivity of a directional relay based on the PSFC or even cause mal-operation. Focusing on this problem, this paper proposes an improved directional relay that is adapted to a distribution network with inverter-interfaced generation (IIG) integration. The improved scheme divides the operation zone of the directional relay based on the PSFC into sensitive and insensitive areas. If the result of a phase comparison is located in the insensitive area, further identification is needed according to a comparison of the current amplitudes. Simulation experiments are carried out based on PSCAD/EMTDC, and their results verify the correctness of the proposed scheme.Energies 2019, 12, 3345 2 of 14 in [11,12]. Unfortunately, [9-12] do not consider the low-voltage ride through (LVRT) requirement of DGs. The traditional DOP may mal-operate in the cases of a wind farm increasing the reactive power output [13]. Reference [13] uses a load encroachment function as a solution, but the function does not consider the effect of high transition resistance. To summarize, problems with directional overcurrent protection may arise in the following two situations:•A high-impedance ground fault, which may result in difficulties with identifying the direction of the fault; • A change in the reactive power output of inverter-interfaced generators (IIGs), which may cause the mal-operation of the traditional directional overcurrent relay.To improve the traditional directional overcurrent protection, the directional relay based on the positive sequence fault component (PSFC) has been widely used due to its ability to withstand transition resistance [14].However, the fault characteristics of DGs are affected by the control strategies, which are different from conventional generators. The directional relay based on the PSFC is not suitable for the distribution network with IIG integration. In [15], the influence of IIGs on the directional relay based on the PSFC was analyzed. The authors pointed out that the phase angle of the equivalent positive sequence abrupt impedance (PSAI) of the IIG will vary from 0 to 180 • , which may lower the sensitivity of the directional relay-or even cause its mal-operation. Unfortunately, no effective solution has been proposed yet.In view of the low sensitivity or mal-operation of the directional relay based on the PSFC for a distribution ...

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“…In Brazil, this has been happening since 2012 [1][2][3]. Due to the increasing adoption of this resource, grid-connected photovoltaic systems (GCPVS) are developing at a very fast pace and will soon be a large part of energy generation in some regions [1,4]. In view of this fact, many countries have established new requirements grid code (GCs) for GCPVS to remain connected during some fault.…”

Section: Introductionmentioning

confidence: 99%

Implementation of a Photovoltaic Inverter with Modified Automatic Voltage Regulator Control Designed to Mitigate Momentary Voltage Dip

et al. 2021

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The main objective of this research is to propose an active and reactive power injection control in order to mitigate voltage sags. The proposed control strategy works in conjunction with a modified version of an automatic voltage regulator (AVR), where it will act on the active and reactive powers injected by the inverter to reduce the effects of voltage sags. In this way, the control will avoid possible shutdowns and damage to the equipment connected to the grid. The voltage improvement can be perceived for consumers connected to the power system. Modifications in AVR model and parameters are performed to speed up its performance, thus identifying the short-duration voltage variations (SDVV) and, consequently, the control acts to alter the powers, decreasing the active power injection and increasing the reactive power based on inverter capacity during the momentary voltage dip (MVD). Finally, when the fault is cleared, all values return to the pre-fault condition, so that the inverter only operates with active power. A 75 kW three-phase grid-connected photovoltaic system (GCPVS) equipped with the proposed control was inserted in a distribution grid of the city of Palmas, state of Tocantins, Brazil, and all of the computer simulations were performed on the Matlab/Simulink®.

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Research on Theoretical Calculation Methods of Photovoltaic Power Short-Circuit Current and Influencing Factors of Its Fault Characteristics

Cited by 16 publications

References 20 publications

A General Mathematical Model for LVRT Capability Assessment of DER-Penetrated Distribution Networks

A General Mathematical Model for LVRT Capability Assessment of DER-Penetrated Distribution Networks

An Improved Directional Relay Adapted to a Distribution Network with IIG Integration

Implementation of a Photovoltaic Inverter with Modified Automatic Voltage Regulator Control Designed to Mitigate Momentary Voltage Dip

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