Bakhtiar I. Saeed

Radiometer monitoring system for partial discharge detection in substation

Progress on the development of an insulation defect detection and location system using a partial discharge (PD) wireless sensor network (WSN) will be presented. Such a PD WSN based on intensity-only measurements has cost and scalability advantages over existing detection and location technologies based on time-difference-of-arrival measurements such as described in (I. E. Portugues, P. J. Moore, I. A. Glover, IEEE Trans. on Power Delivery, 1, 2009, pp. 20–29). Figure 1 shows a hypothetical deployment of the PD WSN in an electricity substation. The (red) pentagram denotes a PD source, yellow circles and triangles denote sensor nodes, and the yellow St Georges cross denotes the data collection/processing node. Each node of the WSN is a broadband radiometer with a measurement band of 50–800 MHz, Figure 2. Three measurement sub-bands allow the radiometer to distinguish different forms of PD; in particular internal PD and corona discharge. WirelessHart has been selected as the network communications technology since this offers improved reliability over other standards (e.g. Zigbee) in harsh industrial environments.

Assessment of absolute partial discharge intensity from a free-space radiometric measurement

Partial discharge (PD) is measured simultaneously using free-space radiometric (FSR) and a galvanic contact measurement technique based on the IEC 60270 standard. The PD source is an emulator of the floating-electrode type. The radiated signal is captured using a biconical antenna. A method of estimating absolute partial discharge (PD) activity level from a radiometric measurement by relating effective radiated power to PD intensity using a PD calibration device is presented.

Comparative study of Partial Discharge emulators for the calibration of Free-Space radiometric measurements

Partial discharge is measured simultaneously using free-space radiometry (FSR) and a galvanic contact measurement technique based on the IEC 60270 standard. Several types of PD (Partial Discharge) sources are specially constructed: two internal PD emulators and an emulator of the floating-electrode type. The excitation applied to the source is AC and the radiated signal is captured using a wideband biconical antenna. The calibration of PD sources is demonstrated. Effective radiated power of the PD source using a PD calibration device is determined.

Wireless sensor network for radiometric detection and assessment of partial discharge in HV equipment

Monitoring of partial discharge (PD) activity within high voltage electrical environments is frequently used for the assessment of insulation condition. Traditional measurement techniques employ technologies that require either offline installation or high power consumption and cost. A wireless sensor network is proposed that utilizes only received signal strength to locate partial discharge within a high-voltage electricity substation. The network comprises low-power and low-cost radiometric sensor nodes which receive the radiation propagated from a source of partial discharge. Results are reported from a test performed within a large indoor environment with a network of nine sensor nodes. An emulated PD source was placed at multiple locations within the network. Signal strength measured by the nodes is reported via WirelessHART to a data collection hub where it is processed using a location algorithm. The results obtained place the measured location within 2 m of the actual source location.

Validation of partial discharge emulator simulations using free-space radiometric measurements

A useful technique to estimate the degradation of insulation in high voltage (HV) installations is the measurement of partial discharge (PD). Free-space radiometric (FSR) detection of PD is a relatively new technique. Several types of PD emulator sources have been constructed: two internal PD emulators and a floating electrode emulator. The emulators have been simulated using the CST Microwave Studio software package. The intention is to use the simulated emulators to establish a relationship between radiated PD signals and PD intensity as defined by apparent charge transfer. To this end the radiated fields predicted in the simulations are compared with measurements. There is sufficient agreement between simulations and measurements to suggest the simulations could be used to investigate the relationship between PD intensity and the field strength of radiated signals.

An ultrawideband patch antenna for UHF detection of partial discharge

The location of partial discharge (PD) sources by free-space UHF detection is an attractive approach for condition monitoring of high voltage equipment in substations. A low-cost, radiometric, PD wireless sensor network (WSN) has been proposed to provide continuous real-time coverage for an entire substation (J.M. Neto, Y. Zhang, A. Jaber, M. Zhu, M. Judd, R. Atkinson, J. Soraghan, J.S. Neto, M.F. Vieira, I.A. Glover, 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), Beijing, 16 – 23 Aug. 2014, pp.1–4). A suggested band for UHF PD detection is 0.3 – 1.5 GHz (Z. Tang, C. Li, X. Cheng, W. Wang, J. Li, IEEE Trans. Dielectr. Electr. Insul., 6, 2006, pp. 1193–1199). A novel ultrawideband (UWB) printed monopole antenna is presented here for PD WSN applications.

Wireless Sensor Network for Radiometric Detection and Assessment of Partial Discharge in High‐Voltage Equipment

Monitoring of partial discharge (PD) activity within high-voltage electrical environments is increasingly used for the assessment of insulation condition. Traditional measurement techniques employ technologies that either require off-line installation or have high power consumption and are hence costly. A wireless sensor network is proposed that utilizes only received signal strength to locate areas of PD activity within a high-voltage electricity substation. The network comprises low-power and low-cost radiometric sensor nodes which receive the radiation propagated from a source of PD. Results are reported from several empirical tests performed within a large indoor environment and a substation environment using a network of nine sensor nodes. A portable PD source emulator was placed at multiple locations within the network. Signal strength measured by the nodes is reported via WirelessHART to a data collection hub where it is processed using a location algorithm. The results obtained place the measured location within 2 m of the actual source location.

Partial discharge detection using software defined radio

Partial discharge (PD) is an electrical discharge that occurs within part of the dielectric separating two HV (High Voltage) conductors. PD causes damage to the dielectric which typically deteriorates with time. If left untreated, PD may result in catastrophic insulation failure, destruction of HV equipment, and disruption of power supply. The emergence of wireless network technology and software defined radio has opened new opportunities in PD monitoring and early detection of failures. This paper proposes the use of Universal Software Radio Peripheral (USRP) technology for PD detection.

Multiple source localization for partial discharge monitoring in electrical substation

This paper studies novel localization methods of multiple partial discharge sources in electrical substations. The three compressive sensing algorithms of Orthogonal Matching Pursuit (OMP), Homotopy technique, and Dichotomous coordinate descent (DCD) are presented. The simulation results demonstrate excellent performance with the compressive sensing methods.

Design of an iterative auto-tuning algorithm for a fuzzy PID controller

Since the first application of fuzzy logic in the field of control engineering, it has been extensively employed in controlling a wide range of applications. The human knowledge on controlling complex and non-linear processes can be incorporated into a controller in the form of linguistic terms. However, with the lack of analytical design study it is becoming more difficult to auto-tune controller parameters. Fuzzy logic controller has several parameters that can be adjusted, such as: membership functions, rule-base and scaling gains. Furthermore, it is not always easy to find the relation between the type of membership functions or rule-base and the controller performance. This study proposes a new systematic auto-tuning algorithm to fine tune fuzzy logic controller gains. A fuzzy PID controller is proposed and applied to several second order systems. The relationship between the closed-loop response and the controller parameters is analysed to devise an auto-tuning method. The results show that the proposed method is highly effective and produces zero overshoot with enhanced transient response. In addition, the robustness of the controller is investigated in the case of parameter changes and the results show a satisfactory performance.