Informatics Publishing Limited

Mohammad Rezazadeh Mehrjou ¹, Norman Mariun ¹, Mahdi Karami ¹, Norhisam Misron ¹, Saman Toosi ¹, Mohammad Reza Zare ¹

Affiliations
1 Department of Electrical and Electronic Engineering, University Putra Malaysia, Selangor, MY

Abstract

Early fault detection of the induction machine is necessary in order to guarantee its stable and high performance. To evaluate the motor's health and detect existence of any failure in it, any motor parameter is first measured using condition monitoring techniques. The raw signal acquired is then interpret applying signal processing and data analysis procedures. Wavelet analysis of the motor current has been considered as an effective fault detection method. However, there are different types of the wavelet function that can be used for signal decomposition. This paper intends to investigate the ability of different types of wavelet functions for early broken rotor bar detection. Different harmonic components introduced by this fault such as maximum wavelet coefficient, left and right gradients of the maximum coefficient, were extracted and used as a characteristic signature for fault detection. The results indicate that the reliability of the fault detection depends on the type of wavelet function applied for decomposition of the signal.

Keywords

Induction Machine, Fault, Broken Rotor Bar, Current Signature, Signal Processing, Wavelet Analysis.

Full Text

   

Athraa Iessa ¹, Noor Izzri Abdul Wahab ¹, Norman Mariun ¹, Hashim Hizam ¹

Affiliations
1 Centre for Advanced Power and Energy Research (CAPER), Department of Electrical and Electronic Engineering, University Putra Malaysia, 43400, Selangor, MY

Abstract

The frequency is one of the instruments for measuring the health status of the power system, due to its ability to anticipate any imbalance between generations and loads. If the generated power is adequate for the system load and losses, then, the system will be in a steady state, otherwise frequency deviates from nominal value due to the mismatch between the generation and load. If the frequency continues to deviate from nominal value, the system may collapse. The assessment of frequency stability level becomes an essential aspect of power system operation and also for projecting the ability of the power system to maintain nominal frequency when subjected to any disturbance. In this paper, a method is proposed to evaluate frequency security of multi-machine power system using transient frequency deviation index (TFDI) which is based on Center of Inertia (COI) referred frequency. The proposed method has been tested on the New England 39- bus test system. Results show that the proposed method takes the advantage of TFDI in accumulating the effect of frequency trajectory deviations. These frequency trajectories may be obtained from the time domain simulation or Wide Area Measurement System (WAMS). The results also show the advantages of COI referred frequency in representing the equivalent frequency of the system. The method would provide a reliable and efficient base for load shedding relays adjustment and operation control.

Keywords

COI Frequency, Frequency Stability Assessment, Transient Frequency Deviation Index, Quantitative Security Assessment.

Full Text