Real-Time Circuit Breaker Availability Assessment in the Transmission Network

Abstract

Circuit breakers (CBs) in the transmission network are the basic elements for energy flow control. CB diagnosis represents a decisive action for increasing power system reliability and safety. Their actual availability status and ability to perform major functions can sometimes be difficult to determine. This paper presents a general state estimation model based on fuzzy logic (FL), membership function (MF), and expert knowledge for diagnosis schemes to handle unclear information in the diagnosis procedure. The proposed model uses inputs from the Supervisory Control and Data Acquisition (SCADA) system, data on the position and state of the switch, changes in current in the network element CB (NECB), start or trip action of a protection relay on the NECB, and alarm status of the CB. For the diagnostic system input variables, data from the SCADA system, along with transformer and line protection devices, are used to allow the proper formation of rules and ultimately to determine the diagnostic status of the CB. The proposed method is tested on an authentic test power system, and the outcome results are compared with a previously reported technique. The obtained test results and the comparison prove the efficiency, authenticity, and fast operation feature of the suggested strategy.

Electrical Life Assessment of the Low-Voltage Circuit Breaker (LVCB) Considering Arc Voltage

“…The study of the change law of CEA with the AST can further analyze the characteristics of supply voltage effect on the electrical life of the LVCB. The CEA curve under different supply voltages is analyzed by Equation (9). The power factor is fixed at 0.65.…”

“…The function f (i e ) can be represented by |i e | or i e 2 . The contact erosion of each operation is calculated by Equation (9). Then, the remaining electrical life of the switching apparatus can be obtained according to the appropriate threshold setting to achieve the purpose of evaluating the electrical life.…”

“…LVCBs are extensively equipped in the distribution network. During the whole life cycle, it is frequently required to design targeted running and maintenance plans, which necessitates a thorough understanding and judgment of the electrical life of LVCBs [9,10].…”

Innovative Integrated Solution for Monitoring and Protection of Power Supply System from Railway Infrastructure

“…Moreover, the electro-erosion of the contacts of existing circuit breakers in electrical power installations in railway traction, according to technical data sheets and/or operating instructions, is assessed by counting the number of disconnections (in the normal and fault regime) and the real value of the disconnected current is not taken into account. This leads to maintenance work being carried out at inappropriate times with regard to the electrical wear of the contacts of these circuit breakers [ 17 , 18 ].…”