scholarly journals Circuit Model and Analysis of Molded Case Circuit Breaker Interruption Phenomenon

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2047
Author(s):  
Kun-A Lee ◽  
Young-Maan Cho ◽  
Ho-Joon Lee

There are complex physical phenomena for the interpretation of a molded case circuit breaker (MCCB) in a distribution system. Most of the studies of MCCB interruption phenomena were conducted with numerical analysis and experiments. This traditional approach may help improve the performance of the MCCB itself, but it is difficult to find connectivity with other systems. In this paper, the circuit model is proposed and the interruption phenomenon of MCCB is analyzed. The interruption of the MCCB is divided into three sections to deal with physical phenomena occurring in each area. A simplified model is proposed considering the characteristics of each section. Based on this model, the circuit model is proposed. To implement the features of each section, the calculation of physical phenomena is carried out, and this is expressed in the circuit model with resistance and zener diode. Comparing the results of the simulation with the experimental results is as follows. For 7-plates (basic state), the error rate is −5.6% in section II and 16.8% in section III. For 1-plate, the error rate is 36.5% in section II and −17.0% in section III. This case shows much difference from the simplified model in this paper, resulting in the largest error rate. The 7-plates and 5-plates cases, which are available in the general MCCB owing to the shortest distance from the arc, represent a relatively small error rate. Using the proposed circuit model, it is expected that the entire system, including the interruption phenomenon, can be interpreted as a single circuit model.

Author(s):  
Adel M Sharaf ◽  
Khaled Mohamed Abo-Al-Ez

In a deregulated electric service environment, an effective electric transmission and distribution networks are vital to the competitive environment of reliable electric service. Power quality (PQ) is an item of steadily increasing concern in power transmission and distribution. The traditional approach to overcoming capacity and quality limitations in power transmission and distribution in many cases is the addition of new transmission and/or generating capacity. This, however, may not be practicable or desirable in the real case, for many of reasons. From technical, economical and environmental points of view, there are two important - and most of the time combined - alternatives for building new transmission or distribution networks to enhance the transmission system capacity, and power quality: the Flexible alternating current transmission devices and controllers, and the distributed generation resources near the load centers. The connection of distributed generation to the distribution grid may influence the stability of the power system, i.e. angle, frequency and voltage stability. It might also have an impact on the protection selectivity, and the frequency and voltage control in the system. This paper presents a low cost FACTS based Dynamic Distribution System Compensator (DDSC) scheme for voltage stabilization and power transfer and quality enhancement of the distribution feeders connected to a dispersed wind generator, using MATLAB/ SimPower System simulation tool.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 334
Author(s):  
Esteban Pulido ◽  
Luis Morán ◽  
Felipe Villarroel ◽  
José Silva

In this paper, a new concept of short-circuit current (SCC) reduction for power distribution systems is presented and analyzed. Conventional fault current limiters (FCLs) are connected in series with a circuit breaker (CB) that is required to limit the short-circuit current. Instead, the proposed scheme consisted of the parallel connection of a current-controlled power converter to the same bus intended to reduce the amplitude of the short-circuit current. This power converter was controlled to absorb a percentage of the short-circuit current from the bus to reduce the amplitude of the short-circuit current. The proposed active short-circuit current reduction scheme was implemented with a cascaded H-bridge power converter and tested by simulation in a 13.2 kV industrial power distribution system for three-phase faults, showing the effectiveness of the short-circuit current attenuation in reducing the maximum current requirement in all circuit breakers connected to the same bus. The paper also presents the design characteristics of the power converter and its associated control scheme.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 338
Author(s):  
Leslie Tracy ◽  
Praveen Kumar Sekhar

In this study, a low voltage solid-state circuit breaker (SSCB) was implemented for a DC distribution system using commercially available components. The design process of the high-side static switch was enabled through a voltage bias. Detailed functional testing of the current sensor, high-side switch, thermal ratings, analog to digital conversion (ADC) techniques, and response times of the SSCB was evaluated. The designed SSCB was capable of low-end lighting protection applications and tested at 50 V. A 15 A continuous current rating was obtained, and the minimum response time of the SSCB was nearly 290 times faster than that of conventional AC protection methods. The SSCB was implemented to fill the gap where traditional AC protection schemes have failed. DC distribution systems are capable of extreme faults that can destroy sensitive power electronic equipment. However, continued research and development of the SSCB is helping to revolutionize the power industry and change the current power distribution methods to better utilize clean renewable energy systems.


The two major concerns in today’s electrical distribution system are the potential damage from fault stress and the costs associated with power outages. The optimal way to limit fault stress is to clear the fault in the shortest amount of time. Unfortunately, clearing the fault within the shortest amount of time might sacrifice coordination and lead to broader power outages. Zone Selective Interlocking Coordination assures the possible sustaining of faults for over currents and voltages with different faults. The circuit breaker operation and principle depend upon the open and close operation for the continuity of supply/service. To reduce the stress on the system, generated energy during fault conditions to be considered and its coordination to be checked


2020 ◽  
Vol 66 (2 Mar-Apr) ◽  
pp. 228
Author(s):  
J. A. Lopez-Leyva ◽  
A. Talamantes-Alvarez ◽  
E. A. Mejia ◽  
J. Estrada ◽  
M. Ponce Camacho ◽  
...  

A Fake Calibration Attack process for a Continuous Variable-Quantum Key Distribution system using a Beam Sampler is presented. The Fake Calibration Attack allows a calibration that balances the Standard Quantum Limit for all the optical path in the experiment (differential Standard Quantum Limit is ≈ 0.39 dB) allowing Eve to acquire ≈ 0.0671 for a particular information quadrature which establishes a Quantum Bit Error Rate ≈ 5.8%. As a final result, the balancing of the Standard Quantum Limit for both states of polarization signals allows maintaining the overall Quantum Bit Error Rate at a particular value ≈ 3%, which implies an important basis for detecting a potential spy considering the minimum Quantum Bit Error Rate.


2011 ◽  
Vol 11 (11&12) ◽  
pp. 937-947
Author(s):  
Hong-Wei Li ◽  
Zhen-Qiang Yin ◽  
Shuang Wang ◽  
Wan-Su Bao ◽  
Guang-Can Guo ◽  
...  

In practical quantum key distribution system, the state preparation and measurement have state-dependent imperfections comparing with the ideal BB84 protocol. If the state-dependent imperfection can not be regarded as an unitary transformation, it should not be considered as part of quantum channel noise introduced by the eavesdropper, the commonly used secret key rate formula GLLP can not be applied correspondingly. In this paper, the unconditional security of quantum key distribution with state-dependent imperfections will be analyzed by estimating upper bound of the phase error rate in the quantum channel and the imperfect measurement. Interestingly, since Eve can not control all phase error in the quantum key distribution system, the final secret key rate under constant quantum bit error rate can be improved comparing with the perfect quantum key distribution protocol.


2022 ◽  
Vol 13 (1) ◽  
pp. 0-0

This paper intends to consider a multi-objective problem for expansion planning in Power Distribution System (PDS) by focusing on (i) expansion strategy (ii) allocation of Circuit Breaker (CB), (iii) allocation of Distribution Static Compensator (DSTATCOM), (iv) Contingency Load Loss Index (CLLI), and power loss. Accordingly, the encoding parameters decide for expansion, Circuit Breaker (CB) placement, DSTATCOM placement, load of real and reactive powers of expanded bus or node are optimized using Grasshopper Optimization Algorithm (GOA) based on its distance and hence, the proposed algorithm is termed as Distance Oriented Grasshopper Optimization Algorithm (DGOA). The proposed expansion planning model is carried out in IEEE 33 test bus system. Moreover, the adopted scheme is compared with conventional algorithms and the optimal results are obtained.


Sign in / Sign up

Export Citation Format

Share Document