Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

Fully electric commercial vessels are becoming increasingly popular, with DC power systems being the preferred choice for onboard power distribution due to their ability to handle high power flows within limited space at higher system efficiency and lower lifecycle costs.Commercial vessels equipped with onboard DC grids have proven capable of operating at peak energy efficiency while minimizing emissions. This results in significant power savings and reduced operating costs across maritime appli

Current Status of Single-Phase Grounding Fault DetectionThe low accuracy of single-phase grounding fault diagnosis in non-effectively grounded systems is attributed to several factors: the variable structure of distribution networks (such as looped and open-loop configurations), diverse system grounding modes (including ungrounded, arc-suppression coil grounded, and low-resistance grounded systems), the increasing annual ratio of cable-based or hybrid overhead-cable wiring, and complex fault typ

The frequency division method enables the measurement of grid-to-ground parameters by injecting a current signal of a different frequency into the open delta side of the potential transformer (PT).This method is applicable to ungrounded systems; however, when measuring the grid-to-ground parameters of a system where the neutral point is grounded via an arc suppression coil, the arc suppression coil must be disconnected from operation beforehand. Its measurement principle is shown in Figure 1.As

The tuning method is suitable for measuring the ground parameters of systems where the neutral point is grounded via an arc suppression coil, but not applicable to ungrounded neutral point systems. Its measurement principle involves injecting a current signal with continuously varying frequency from the secondary side of the Potential Transformer (PT), measuring the returned voltage signal, and identifying the system's resonant frequency.During the frequency sweeping process, each injected heter

In an arc - suppression coil grounding system, the rising speed of the zero - sequence voltage is greatly affected by the value of the transition resistance at the grounding point. The larger the transition resistance at the grounding point, the slower the rising speed of the zero - sequence voltage.In an ungrounded system, the transition resistance at the grounding point has basically no impact on the rising speed of the zero - sequence voltage.Simulation Analysis: Arc - suppression Coil Ground

I. Overvoltage PreventionVacuum circuit breakers excel in interrupting performance, but high overvoltage may occur across inductors during the switching of inductive loads due to abrupt changes in loop current, which requires special attention. When switching small-capacity motors, starting currents are large, so measures like step-down starting should be adopted to limit the current.Transformers with different structures show distinct characteristics: oil-immersed transformers have high impulse

In the first half of 2007, as project participants from the Electromechanical Equipment Company of Huaibei Mining Group, we carried out a technical transformation of the 10kV substation in the East Factory Area. Our primary task was to replace the original 10kV disconnector - oil - immersed circuit breaker units with ZN20 indoor high - voltage vacuum circuit breakers.Previously, the SN10 - 10 oil - immersed circuit breakers had been in operation for an extended period, leading to severe oil leak

Inability to Push In or Withdraw the Draw-out CarriageThe main manifestation is difficulty in inserting the carriage, which may cause equipment damage and threaten production when severe. The causes and countermeasures are shown in Table 1.The circuit - breaker fails to close. It manifests as the closing core actuating but the circuit - breaker not closing successfully; or the closing core not actuating, which shows that the control circuit of the circuit - breaker is open - circuited or the mec

In power system operation and maintenance, we have found that 35kV and 10kV indoor vacuum circuit breakers, as core primary equipment of high-voltage switchgear, are widely used in main grid and user substations due to their high reliability and low maintenance workload. From daily inspections and live detection to routine maintenance, vacuum circuit breakers always remain our key focus, as their operational quality is directly related to the stability and reliability of the power system. This p

Vacuum circuit breakers are widely used in distribution networks. As core components of power supply equipment, their performance hinges on both vacuum interrupters’ capabilities and circuit breakers’ mechanical characteristics (contact opening distance, stroke, pressure, average closing/opening speed, closing bounce time, opening - closing asynchronism, operation times, and cumulative allowable wear of contacts). Both are critical for reliable operation. The vacuum interrupt