With its state-of-the art infrastructure and expertise, CPRI has made significant contributions to the power sector in the country for improved planning, operation and control of power systems. CPRI is able to capture real-world experience and best practices in an ever-expanding White Paper repository.
This white paper repository is part of a collection of technical documents produced by CPRI experts to address challenges and developments in power sector.
Towers are the most important component of the overhead power transmission line system. When failure occurs, direct and indirect losses are very high; hence accurate prediction of tower failure becomes very important for the reliability and safety of the transmission system. One cannot accurately predict the behavior of tower after practical loading conditions, so testing of tower for various loading conditions before installing in field becomes very important. The present paper discusses the structural behavior of towers during full scale testing carried out at Central Power Research Institute, Bangalore, India. Although, the towers were safe for various loading conditions based on the design/analysis, during full scale testing, different types of premature failures were observed. Necessary modifications in towers have been carried out and these towers were retested successfully. The details of remedial measures / strengthening of members carried out during testing are brought out in this paper.
In recent years, due to advancement of technology, the transmission voltage levels are goes on increasing. Worldwide 800 kV systems is very common and in India experimental 1200 kV AC is successfully commissioned. Testing of vital equipment of such UHV transmission network is paramount importance to provide uninterrupted, reliable and quality power to the customers. Worldwide few testing laboratories having facility to test upto UHV class equipment, the Ultra High Voltage Research Laboratory (UHVRL) of Central Power Research Institute (CPRI), India is one among them. Recently, 2X600 kV, 2 A, 2400 kVA HVAC test system is commissioned in double shielded indoor laboratory at UHVRL, Hyderabad, India. This manuscript elaborates the experiences of commission of AC test system along with radio interference voltage and Partial Discharge (PD) measurement.
Relays are the protection and switching devices in most of the control processes or equipment. Relays respond to one or more electrical quantities like voltage or current such that they open or close the contacts or circuits. Relays are subjected to vibration and mechanical shock due to operating environment, transportation, mishandling and earthquake. Operating environmental vibration and shock may result in spurious operation of relays. Understanding cause and effect of vibration on relay performance is paramount to ensure reliable functioning of relays. Relays should be designed for the anticipated operating environmental vibration and shock levels. Vibration and shock qualification is performed to determine if a product can withstand the rigors of its intended use environment, to insure the final design will not fall apart during shipping, for environmental stress screening and to weed out production defects. CPRI is equipped with state-of-the-art facilities to qualify equipment and components for vibration and shock conditions. Performance of relay under vibration environment is discussed in this paper.
For modern high-power LEDs, self-heating becomes a critical factor determining their functional characteristics and lifetime. For large-area LEDs with a complex structure, it is important to know not only the thermal resistance but also the detailed temperature distribution (temperature map) over the active area. In this paper, we present the thermal analysis of high-power Light-Emitting Diodes (LEDs) with under the real operating conditions. Thermal transient measurements were performed to study the thermal characteristics of high power LED bulbs. The purpose of this test is to analyze the heat dissipation from LED Lamps. The study concludes that the warm white LED bulbs show better thermal behavior than the cool white LED bulbs of low power.
The challenge with solar energy prediction is that the solar radiation is intermittent and uncontrollable. Energy forecasting can be used to mitigate some of the challenges that arise from the uncertainty in the resource. Weather data was sourced from India Meteorological Department for Bangalore and Chennai location. This paper provides statistical approach to predict the solar power in future. Analysis was done for different predictive models; Multiple Regression Model is used as we have multiple inputs. The results indicate the prediction of solar radiation has better accuracy during higher irradiation period rather than lower irradiation period.