Informatics Publishing Limited

J. Pradeep Kumar Rao ¹, H. N. Nagamani ², V. Vaidhyanathan ³, T. Bhavani Shanker ⁴

Affiliations
1 Senior Research Fellow, Capacitors Division, Central Power Research Institute, Bangalore- 560080, IN
2 Ex-Addl Director, Capacitors Division, Central Power Research Institute, Bangalore- 560080, IN
3 Engineering Officier – III, Capacitors Divison, Central Power Research Institute, Bangalore – 560080, IN
4 Joint Director and HOD, Capacitors Division, Central Power Research Institute, Bangalore – 560080, IN

Abstract

The paper focuses on accepting Hybrid ultra-capacitors as working capacitors from a huge number of unconditioned ones. Hybrid ultra-capacitors of 12 V/2500 F range are evaluated for their performances. Healthy and faulty behavior of these capacitors is analyzed in terms of voltage discharge characteristics. Synthesis of lead carbon hybrid ultra-capacitors of 12 V/2500 F range from electrode to container form is discussed. The steps need to be followed to identify the healthy capacitors from the faulty capacitors are presented. Procedure developed for pre-conditioning of HUCs, performance evaluation and failure analysis results are discussed. From discussion, the condition for acceptance of 12 V/2500 F range Hybrid ultra-capacitor as an energy storage system for solar power applications is formulated.

Keywords

Pb – C HUC/HUC – lead carbon hybrid ultra-capacitor, constant voltage charging time duration.

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J. Pradeep Kumar Rao ¹, H. N. Nagamani ², V. Vaidhyanathan ³, T. Bhavani Shanker ⁴

Affiliations
1 Senior Research Fellow, Capacitors Division, Central Power Research Institute, Bangalore- 560080, IN
2 Ex-Addl Director, Capacitors Division, Central Power Research Institute, Bangalore- 560080, IN
3 Engineering Officer – III, Capacitors Division, Central Power Research Institute, Bangalore – 560080, IN
4 Joint Director and HOD, Capacitors Division, Central Power Research Institute, Bangalore – 560080, IN

Abstract

The paper discussess ome of the practical issues on direct parallel integration of lead acid battery and lead carbon hybrid ultra-capacitor to form an integrated energy storage system for solar power applications. The integrated energy storage system is subjected to various C rates to analyze the behavior of charging and discharging of HUC. The percentage contribution of HUC, in charging and discharging of the integrated energy storage system would be a useful information, while coupling battery and HUC in solar power applications. In view of this, experimental studies have been carried out at different C rates and results are presented.

Keywords

Pb - C HUC/HUC - Lead carbon Hybrid Ultra-capacitor, C rates, an integrated energy storage system

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H. N. Nagamani ¹, T. Bhavani Shanker ¹

Affiliations
1 Central Power Research Institute, Bangalore - 560080, IN

Abstract

Power transformers play a vital role in handling large amount of power from generating stations [through Generating Station Units(GSU] to transmitting stations (through power transformers) and to end user through distribution transformers. Power transformers involve large amount of capital investment and the failure of transformers causes severe fi nancial loss to the utility and inconvenience to the end users. Periodic maintenance and condition monitoring are the key factors for successful operation of power transformers. A number of diagnostic tools are in vogue. Most of these tests are conventionaloff-line techniques and require power shut down and disconnection of transformer from the circuit. Several alternate nonconventional on-line techniques are being adopted and Acoustic Emission (AE) technique is one among them. Central Power Research Institute (CPRI), India, is employing AE technique for on-line diagnosis of power transformers. Nearly 200 transformers have been tested and investigated covering rating up to 315 MVA, 400 kV.

The paper discusses some of the important aspects of on-line diagnosis of oil-fi lled power transformers employing AE technique. A few important case studies which have helped utilities and transformer manufacturers for initiating corrective actions are covered in the paper.

Keywords

On-line diagnosis, Off-line diagnosis, Insulation diagnosis, Condition monitoring, Transformers, Partial discharge, Acoustic emission.

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T. Bhavani Shanker ¹, Shyam Ravichandran ¹, V. Vaidhyanathan ¹, A. Sheik Mohamed ¹

Affiliations
1 Capacitor Division, Central Power Research Institute, Bengaluru – 560012, Karnataka, IN

Abstract

Localised power generation and consumption using a solar-based hybrid micro-grid system are gaining predominance in remote locations where conventional transmission of power from far off substations work out to be uneconomical. Since the peak irradiance from the sun lasts for 4-6 hours per day, a hybrid micro-grid with batteries for storing energy is usually adopted. This study considered a typical household load of 3kW comprising resistive and inductive loads. Sudden surges will be caused by switching ON/OFF of any load, and in particular, switching ON of inductive loads (such as fans, washing machines and mixer) will further contribute to transients. These sudden changes in loads harm the cyclic life of the battery. A viable solution to overcome the above problem is to use Hybrid Ultra Capacitors (HUC) as an assistant to the Batteries. These HUC banks can take over the surge loads, whereas Batteries can focus on delivering steady power. Such a combination has the potential to enhance the battery’s life. This study discusses the performance of Hybrid Ultra Capacitor (HUC) based Hybrid Energy Storage System (HESS) in a 3kW Solar MicrogriAU: Please prod system by evaluating the electrical parameters involving experiments with different loads.

Keywords

Electric Vehicles, Hybrid Ultra Capacitors, Power Batteries, Solar Micro-grid.

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