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Transformered Photovoltaic (PV) system is the common way of integrating PV system with the grid. Inrush current drawn by transformer may affect the stability of PV system. The severity of problem enhances due to intermittent nature of PV system. Analysis of PV system under inrush current condition is analyzed in terms of its limited short circuit capacity. This paper proposes mitigation of inrush...
In Indonesia, there are many capacitor bank installed to regulate the nominal voltage. Currently, the Recovery Voltage (RV) data related to the capacitor bank switching is unavailable, whereas this data is very important to analyze Circuit Breaker (CB) performance to understand whether it will success to interrupt the current or not. In addition, if the CB cannot retain the RV, it will degrade the...
The change of operating conditions by circuit breaker switchings or initiation of emergency conditions (short circuits) is accompanied with transient processes. The physical nature of a transient process is redistribution of the stored energy between inductive and capacitive network elements. In some cases, circuit breaker opening may induce high-frequency overvoltages, while circuit breaker closing...
Capacitor switching is one of the most important sources of generating transient overvoltage and inrush current of electrical power system. Energizing transient may reduce the life span of capacitor banks, damage of power system equipment and insulation failure. This paper, presents three technologies used to mitigate transients caused by capacitor switching. ATP program is used to simulate capacitor...
According to the specifications in IEEE 1894-2015, a transient process measuring device (TPMD) is developed to be used in the distribution system, and a line selection technique utilizing large pulse current is presented on this basis. When a single-phase grounding fault occurs, the distribution system is able to be instantly switched from grounding with small current to grounding with large pulse...
Controlled switching is a solution for the reduction and elimination of high frequency transient currents and voltages that occur during the switching of reactive plant (shunt capacitor banks and reactors). This type plant may be frequently switched by system operators in order to maintain acceptable voltage limits and therefore if switching is uncontrolled, this may present significant power quality...
Shunt capacitors provide a cost-effective solution to alleviate voltage constraints in HV/EHV power systems and are widely used for voltage and reactive support. However, during planning and design phase, engineers are often faced with a challenge to choose appropriate transient mitigation/control arrangements ranging from pre-insertion resistors/inductors and current limiting reactors (CLRs) to synchronous...
Mechanically switched capacitors (MSC) are very well known reactive power compensation devices which are extensively in use in power transmission systems. However, during switching of MSC in a high voltage grid, significant transients are found to appear across the capacitor bank bus as well as different elements of MSC which may lead to insulation degradation affecting the long term performance of...
This paper presents a Cuckoo Search meta-heureustic optimization method to shunt capacitor placement on distribution systems under capacitor switching constraints. The optimum capacitor allocation solution is found for the system of feeders fed through their transformer and not for any individual feeder. The main advantages due to capacitor installation, such as capacity release and reduction of overall...
Numerous industrial facilities involve the installation of load transformers with their respective loads. As loads are turned on and off, these transformers are energized and de-energized, respectively, which can cause serious disturbances to sensitive loads. An inrush current, which typically occurs when a transformer is energized, can easily be observed using on-line uninterruptible power supply...
The switching transient is not a new phenomenon; it has been around for many decades. Recently, it has received more attention, because of the failure of some dry-type transformers that are mainly used in data centers. This paper investigates fast interrupting switching devices, especially vacuum circuit breakers (VCBs). The following questions were investigated: How does a VCB generate transients?...
Transient overvoltages are normal. Insulation must withstand not only the functional voltage, but also the transient overvoltages. A scheme called “insulation coordination” has been instituted by the International Electrical Commission to promulgate and standardize on coordinating the transient overvoltage suppression with insulation electric strength. This paper addresses the insulation requirements...
A life in modern society without safe and reliable supply of electricity is almost unimaginable, as it plays an indispensable role in human life. This reliability, essentially the balance is very important for safe operation of electronic appliances, but failures by transients become more prevalent due to their higher susceptibility of control circuits. Therefore either it should be reduced or eliminated...
The EER (Envelope Elimination and Restoration) architecture is high efficient power control method for high frequency power amplifiers. The EER architecture has a feature of high efficiency operation for the high PAPR system such as QAM and OFDM. However, due to slow transient attenuation of the tuned power amplifiers, actual EER system cannot achieve expected power level and efficiency. In order...
Scattered installation characteristic of CCHP system endows itself as a very favorable black-start unit, where inrush current plays as a significant factor in the process of black-start which need to be analyzed. To mirror the act of inrush current in such a case, the CCHP system based black-start model is established using the PSCAD simulation tool. In order to unveil the inrush current activity...
The EER transmission system was introduced to exploit high efficiency switching power amplifiers in the high PAPR transmission systems such as QAM and OFDM. However, due to transient attenuation characteristics of the tuned switching power amplifiers, EER systems suffered from low power efficiency in the actual transmission systems. EPWM architecture was introduced to improve power efficiency of the...
In this paper, two technologies are used to mitigate transients caused by capacitor switching in distribution feeders. The basic concept of capacitor bank switching transients and its mitigating techniques is presented here. The MATLAB /SIMULINK software is used to simulate the energization of a controlled capacitor bank in a specific substation feeder, with and without employing mitigation devices...
The paper explains the necessity of the development of additional technical requirements for medium voltage vacuum circuit breakers (VCB). Based on experimental investigations, possibility of significant difference in electrical and mechanical characteristics for VCB of various manufacturers is stated. It is shown that associated parameters of electrical and mechanical transient processes at VCB switchings...
In this paper, the energy transient response during circuit breaker operation for shunt reactor is simulated. To recreate the energy transient phenomenon which occurs during reactive power switching, modeling for Electro Magnetic Transients Program (EMTP) are well established and analyzed. Following this, methods for improving transient recovery voltage (TRV) during switching of reactive power supply...
In this paper, switching overvoltages are studied on part of 380 kV interconnected network of Central Anatolia of Turkey, which contains six busbars that are interconnected with five different transmission lines of different lengths and geometries. The studies are carried out by an electromagnetic transient software program called PSCAD/EMTDC. Overvoltages that take place due to energizing a line...
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