The aim of this paper is to discuss the important features of wavelet transform and other existin... more The aim of this paper is to discuss the important features of wavelet transform and other existing methods in compression of fingerprints. Image quality is measured objectively using peak signal-to-noise ratio (PSNR). A comparative study among discrete cosine transform based joint photographic experts group (JPEG) standard, embedded zerotree wavelet (EZW) scheme and JPEG2000 is done. The study shows that EZW and JPEG2000 results in compression ratio 40:1 which is much higher than the existing FBI wavelet/scalar quantization (WSQ) standard that offers best compression at 26:1. Our results helps application developers to choose a good wavelet compression system for their applications.
The aim of our paper is to examine a set of wavelet functions for implementation in an electrocar... more The aim of our paper is to examine a set of wavelet functions for implementation in an electrocardiogram (ECG) image compression system. Eight different wavelets are evaluated for their ability to compress ECG as image. Image quality is compared objectively using mean square error (MSE) and peak signal to noise ratio (PSNR) along with visual appearance. Results show that clinically
This paper proposes a simple methodology for placing two principal types of DG units - synchronou... more This paper proposes a simple methodology for placing two principal types of DG units - synchronous machine and induction machine with an objective of enhancing loadability of distribution system. The proposed methodology is based on the concept of reactive power margin. Buses have been ranked based on the reactive power margin and grouped as “strong” and “weak” buses for finding suitable location of DG units. The effect of size of DG unit on loadability is also examined along with grid loss measure which leads to suitable size selection. The proposed methodology is successfully applied to a modified 16 bus primary distribution system using a commercially available analytical tool and the results are verified using a research analytical software tool.
The penetration level of renewable based distributed generation (DG) has increased rapidly in rec... more The penetration level of renewable based distributed generation (DG) has increased rapidly in recent years. Grid standards demand small DG units to operate with constant power factor control mode and large DG units with voltage control mode. As a result, small DG units are exposed to the problem of slow voltage recovery due to contingencies like fault. This paper proposes a new sensitivity index based methodology for placement of shunt reactive power compensators to support voltage at load bus and generator bus under steady state and transient conditions. Two different test systems with diverse network and load configurations have been used to test and verify the proposed methodology.
Wide-scale penetration of small distributed generation (DG) units to weak distribution systems is... more Wide-scale penetration of small distributed generation (DG) units to weak distribution systems is one of the major concerns for power system engineers. As grid standards limit reactive power generation capability of small DG units, lack of sufficient reactive power support, brings the problem of slow voltage recovery under post-fault conditions. In this paper, a STATic COMpensator (STATCOM), which is chosen as a dynamic volt-ampere reactive (VAR) compensator has been placed in DG integrated systems based on a new index. Impact of index based placement of STATCOMs on angle stability has been investigated in details with both modal and time domain analyses. Simulation results confirm satisfactory voltage recovery and damping improvement with index based placement of STATCOMs. An IEEE industrial mesh system with various dynamic motor loads is used to validate the effectiveness of the proposed STATCOM placement technique.
Integration of small distributed generation (DG) units to weak distribution system is a major con... more Integration of small distributed generation (DG) units to weak distribution system is a major concern for power system engineers. Recent grid standards demand small DG operation with power factor control mode. Lack of sufficient reactive power support brings the problem of slow voltage recovery under post-fault condition. This paper presents a comprehensive VAR planning with a mixture of both static and dynamic compensators. In a system with number of DG units, a suitable location has been sorted out for minimum number of STATic COMpensator (STATCOM) to keep DG units remain interconnected. With help of cost analysis, STATCOM rating has been minimized to ensure economic voltage restoration, which eventually increase DG intake in distribution system. An IEEE industrial test system with various motor loads has been used for simulation and analysis.
Recently, establishing reliable index to assess voltage stability condition of a stressed multi-n... more Recently, establishing reliable index to assess voltage stability condition of a stressed multi-node power transmission and distribution system is getting lot of attention. With the integration of renewable energy in power system the subject of voltage stability in distribution system is getting more interest. In this study, reactive power margin has been used as a stability index which appears as a reliable index to determine critical or weak node while considering the influence of load uncertainties. Effectiveness of reactive power margin index has been proved using a modified 16 bus primary distribution system. Some important results are presented in this paper.
The aim of this paper is to discuss the important features of wavelet transform and other existin... more The aim of this paper is to discuss the important features of wavelet transform and other existing methods in compression of fingerprints. Image quality is measured objectively using peak signal-to-noise ratio (PSNR). A comparative study among discrete cosine transform based joint photographic experts group (JPEG) standard, embedded zerotree wavelet (EZW) scheme and JPEG2000 is done. The study shows that EZW and JPEG2000 results in compression ratio 40:1 which is much higher than the existing FBI wavelet/scalar quantization (WSQ) standard that offers best compression at 26:1. Our results helps application developers to choose a good wavelet compression system for their applications.
The aim of our paper is to examine a set of wavelet functions for implementation in an electrocar... more The aim of our paper is to examine a set of wavelet functions for implementation in an electrocardiogram (ECG) image compression system. Eight different wavelets are evaluated for their ability to compress ECG as image. Image quality is compared objectively using mean square error (MSE) and peak signal to noise ratio (PSNR) along with visual appearance. Results show that clinically
This paper proposes a simple methodology for placing two principal types of DG units - synchronou... more This paper proposes a simple methodology for placing two principal types of DG units - synchronous machine and induction machine with an objective of enhancing loadability of distribution system. The proposed methodology is based on the concept of reactive power margin. Buses have been ranked based on the reactive power margin and grouped as “strong” and “weak” buses for finding suitable location of DG units. The effect of size of DG unit on loadability is also examined along with grid loss measure which leads to suitable size selection. The proposed methodology is successfully applied to a modified 16 bus primary distribution system using a commercially available analytical tool and the results are verified using a research analytical software tool.
The penetration level of renewable based distributed generation (DG) has increased rapidly in rec... more The penetration level of renewable based distributed generation (DG) has increased rapidly in recent years. Grid standards demand small DG units to operate with constant power factor control mode and large DG units with voltage control mode. As a result, small DG units are exposed to the problem of slow voltage recovery due to contingencies like fault. This paper proposes a new sensitivity index based methodology for placement of shunt reactive power compensators to support voltage at load bus and generator bus under steady state and transient conditions. Two different test systems with diverse network and load configurations have been used to test and verify the proposed methodology.
Wide-scale penetration of small distributed generation (DG) units to weak distribution systems is... more Wide-scale penetration of small distributed generation (DG) units to weak distribution systems is one of the major concerns for power system engineers. As grid standards limit reactive power generation capability of small DG units, lack of sufficient reactive power support, brings the problem of slow voltage recovery under post-fault conditions. In this paper, a STATic COMpensator (STATCOM), which is chosen as a dynamic volt-ampere reactive (VAR) compensator has been placed in DG integrated systems based on a new index. Impact of index based placement of STATCOMs on angle stability has been investigated in details with both modal and time domain analyses. Simulation results confirm satisfactory voltage recovery and damping improvement with index based placement of STATCOMs. An IEEE industrial mesh system with various dynamic motor loads is used to validate the effectiveness of the proposed STATCOM placement technique.
Integration of small distributed generation (DG) units to weak distribution system is a major con... more Integration of small distributed generation (DG) units to weak distribution system is a major concern for power system engineers. Recent grid standards demand small DG operation with power factor control mode. Lack of sufficient reactive power support brings the problem of slow voltage recovery under post-fault condition. This paper presents a comprehensive VAR planning with a mixture of both static and dynamic compensators. In a system with number of DG units, a suitable location has been sorted out for minimum number of STATic COMpensator (STATCOM) to keep DG units remain interconnected. With help of cost analysis, STATCOM rating has been minimized to ensure economic voltage restoration, which eventually increase DG intake in distribution system. An IEEE industrial test system with various motor loads has been used for simulation and analysis.
Recently, establishing reliable index to assess voltage stability condition of a stressed multi-n... more Recently, establishing reliable index to assess voltage stability condition of a stressed multi-node power transmission and distribution system is getting lot of attention. With the integration of renewable energy in power system the subject of voltage stability in distribution system is getting more interest. In this study, reactive power margin has been used as a stability index which appears as a reliable index to determine critical or weak node while considering the influence of load uncertainties. Effectiveness of reactive power margin index has been proved using a modified 16 bus primary distribution system. Some important results are presented in this paper.
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