Low-voltage AC Series Arc Fault Detection Method And Module Design

With the increasing emphasis on electrical safety,low-voltage AC series arc fault detection methods have attracted more scholars’ attention.Due to the wide variety of loads and the high randomness of the arcing process,most of the current detection methods can only effectively detect one or a few types of simple loads,and some detection methods have large computational complexity and are difficult to implement on low-power microprocessors.,This article takes a certain type of circuit breaker as the research object to study an arc fault detection method that is suitable for a variety of loads and is easy to integrate into the circuit breaker.A control module that can be assembled into the circuit breaker is designed to provide an effective reference for the intelligent design of the circuit breaker.Firstly,according to the structural characteristics of the circuit breaker,because it is not equipped with an auxiliary power interface and the space structure is limited,the power supply mode of the control module is determined to be CT induction.Research the key parameters that affect the output power of the electric CT and quantitatively analyze the corresponding relationship between each parameter and its output power,and deduce the matching parameters that can make the electric CT work at the maximum electric power state and the maximum output power under the current parameters;Simulate and analyze the push-pull electromagnet,study the relationship between the coil current and the force of the electromagnet moving iron core,and then determine the output voltage of the electric CT;measure the power consumption of the control module of the whole machine,and determ ine the output power of the electric CT;Power CT simulation calculation,parameter scanning,calculate the output power of the power CT at the current operating point,and find the power CT design parameters that meet the power consumption of the control module and have the smallest volume.Secondly,conduct experiments on resistive,inductive,non-linear,and shielding loads,collect arc fault current waveforms under different loads,analyze the difference between arc fault current and normal operating cu rrent,and determine the key characteristics of arc fault current;according to this Features.A small-sized,non-saturable high-frequency current sensor is used to collect arc fault current,and its transmission characteristics at different frequencies ar e analyzed.9 sets of experiments are carried out under different loads and compared with actual arc faults.The current waveforms are compared to determine its feasibility;finally,a low-voltage AC series arc fault detection method is designed for high-frequency current sensors,which can ensure a high detection rate and zero misjudgment rate in the load under test.Finally,design the control module of the circuit breaker.First,determine the overall design plan of the control module according to the index requirements of the circuit breaker;secondly,design the energy storage circuit and signal acquisition module according to the design parameters of the control module;then,solve the inverse time equation according to the trip protection action time of the circuit breaker,and design the software to achieve The circuit breaker’s long time delay,short time delay,instantaneous three-stage protection and three-phase unbalance protection;finally,the control module and the circuit breaker body are assembled and tested.