Mohamed E. Ibrahim

Differential Reconstruction Method for Power Frequency AC Current Measurement Using Rogowski Coil

In this paper, a developed method for measuring power frequency ac current using Rogowski coil is presented. The proposed method uses a differentiator in order to reconstruct the current that is intended to be measured. This method gives accurate results as well as it requires only few samples to successfully reconstruct the power frequency current. These advantages are investigated by experimental testing using two different designs of Rogowski coil. The first Rogowski coil has a higher number of turns as compared with the second one. In addition, a digital signal processor is integrated with the coil to implement the proposed reconstruction method. The obtained results give an evidence for the proposed method validity as well as its efficacy.

Effect of washing water flow rate and pollution level on leakage current of a fixed washed high voltage insulator

Fixed washing system is one of the most common techniques for cleaning high voltage insulators in generation power stations. This paper presents an experimental study to investigate the effect of washing water flow rate as well as the equivalent salt deposit density (ESDD) on the leakage current passes over a high voltage insulator surface during the washing process. This investigation is carried out using a reduced experimental model that closely simulates the real washing system. Different washing water flow rates are used during the experiments and leakage currents are recorded at each case. Each washing flow rate is studied at different ESDDs that covers light to very heavy pollution levels according to the IEC 60507 standard. Also, leakage currents are recorded using a data acquisition system consists of a digital signal processing (DSP) board and a computer. Based on the obtained leakage current results, different washing methods are proposed to achieve an efficient washing system that reduces the chance of flashover occurrence.