Continuous Remote Online Partial Discharge Monitoring of HV Ex/ATEX Motors in the Oil and Gas Industry

Abstract

This paper presents results from the continued application of a new technique for the remote online partial discharge (OLPD) testing and monitoring of in-service high-voltage (HV) explosive atmosphere (Ex)/atmosphere-explosive (ATEX) motors operating in hazardous gas zones. The technique employs highcurrent wideband high-frequency current transformer sensors located remotely from the motor under test, at the switchboard end of the HV feeder cable. Significant cost and operational benefits can be gained from this remote monitoring technique as the stator winding condition of these motors can be monitored without having to enter the hazardous gas (Ex/ATEX) zone. The work described in this paper is a continuation of that carried out by the same authors, as reported at the 2012 IEEE Petroleum and Chemical Industry Technical Conference, and includes the development of proposed condition guidelines for assessing the condition of the stator winding insulation systems of large populations of aged HV motors, based on an OLPD "league-table" database. Two case studies are presented wherein the HV stator insulation condition and reliability of in-service motors, operating in hazardous gas zones, and HV generators were assessed using both online and offline partial discharge (PD) testing and monitoring techniques. The case studies emphasize the importance of carrying out extended continuous OLPD monitoring of in-service rotating HV machines to detect underlying trends in PD activity over time. This paper concludes with how condition monitoring data can support reliability-centered maintenance and condition-based management regimes.Index Terms-Condition-based management (CBM), explosive atmosphere (Ex) and atmosphere-explosive (ATEX) motors, hazardous gas zones, online partial discharge (OLPD), partial discharge (PD), PD diagnostics, phase-resolved PD, rotating high-voltage (HV) machines.

Practical aspects of partial discharge measurement for HVDC cables

“…Partial discharge (PD) is a well-known indicator of insulation ageing and degradation under AC conditions. Online PD monitoring of AC power equipment has been employed by operators in the context of condition-based and predictive maintenance [10]. Under pure DC conditions, PD has received less attention because it is less directly associated with causing insulation degradation and breakdown [11].…”

The Role of Right Interpretation of Space Charge Distribution for Optimized Design of HVDC Cables

“…N high voltage systems, especially under AC stress, the partial discharges phenomena are considered the main dielectric degradation causes [1][2][3][4][5]. In high voltage direct current (HVDC) systems, instead, the space charge This paragraph of the first footnote will contain the date on which you submitted your paper for review.…”

Optimization of a High-Frequency Current Transformer Sensor for Partial Discharge Detection Using Finite-Element Analysis

“…The HFCT often has a split-core design, making it easy to install and suitable for retrofit installations. Also, HFCTs have good sensitivity and wide bandwidth making them ideal for remote monitoring [4]. When designing an inductive sensor, such as an HFCT, it is common to use equivalent circuits [5] or simplified models [6] to optimize its parameters.…”