Gujarat Technological University 2011-7th Sem B.E Electrical Engineering , Advance Power System-1 - Question Paper

GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEM-7 Examination-Nov/Dec.-2011
Date:26/11/2011
Total Marks:70
Subject code:170904
Subject Name:Industrial Instrumentation
Q-1(a) discuss various methods of reactive power control.
(b) explain advantage of FACTs.
Q-2(a) discuss working of STATCOM with schematic diagram.
(b) Compare HVDC and EHVAC transmission system.
OR
(b) discuss UPFC control with neat schematic diagram.
Q-3(a) discuss schematic diagram of HVDC substation and discuss working of every component in brief.
(b) What is HVDC-VSC system? provide single line diagram of the system.
OR
Q-3(a) For a lossless distributed parameter symmetrical line derive the formula for the midpoint voltage on the line in terms of wave number and surge impedance of the line. Also draw graph for the distribution , midpoint voltage v and load angle.
(b) discuss working of TCR draw wave forms of voltage and current for various values of alpha.
Q-4(a) Identify the different sources for generation of harmonics in HVDC system. explain different adverse
effects caused due to presence of harmonics.
(b) Comparison ranging from classical HVDC and HVDC-VSC system.
OR
Q-4(a) provide schematic diagram of 12 pulse converter. discuss various conduction modes.
(b) State differences in power control in HVDC and HVAC system. discuss the necessity of power control in an HVDC link.
Q-5(a) With relevant diagram discuss operation of IPC schemes employed in control schemes of firing circuit of HVDC station. discuss operation of cosine control of phase delay used in above schemes.
(b) discuss extinction angle control ? elaborate its limitations under asymmetrical fault ?
OR
Q-5(a)What is IGBT ? Draw its symbol and explain important features of IGBT. List cause for selection of IGBT. List cause for selection of IGBT for VSC based HVDC conversion.
(b) Sketch the current waveform of the transformer secondary line current of a 12 pulse converter. Derive expression for PIV and PPR for 12 pulse converter.

Earning:   Approval pending.