Skip to main content

Posts

Dr.VAM Blog crossed 5 Million Views

  5 Million - 5 Lakh - 500K Dr.VAM blog is created as 'Arivumani Blog' on 09.09.2009. This blog is nearly 3000 posts. This blog views now crossed 5 Million visitors. new Posts will be coming soon.  Now the blog is hosted in the domain drvam.nqh.in Keep visiting
Recent posts

Ekura Circle - Determine Emakandam, Kuligai and Rahukaalam in Clock circle

  எ கு ரா -  எமகண்டம்,  குளிகை  மற்றும்  ரா கு காலம், ஒரே வட்டத்தில்

Neutral Voltage Ratio (NVR) and Earth Tangent Angle (ETA)

  Instantaneous Neutral Voltage (Vn) is the Phasor sum of all phase voltages. It is Zero in Three phase three wire system, and Three phase Four wire  Balanced System.  Let us introduce the New Factor namely 'Neutral Voltage Ratio (NVR)' which is the Ratio between the RMS of Neutral Voltage and Sum of All Phase voltage RMSs. It is approximately equal to the sine of ETA. ETA is the Angular Symmetrical Component represents the zero sequence voltage. Sine of ETA is the ratio between Zero sequence Voltage and SEL Voltage. Zero sequence voltage is 57.735% of Neutral Voltage. SEL Voltage is 1.732 times of the Quadratic Mean of Phase Voltage RMS values. Mean square of Phase Voltages are equal to the square of Average phase voltage and  Square of Standard deviation (Variance) of phase voltages.  Sine of ETA is apparently equal to the NVR defined above after detailed derivation given below. So, ETA will apparently determined as Arc Sine of NVR. Hence, NVR is also called a...

Angular Symmetrical Components for Currents

            Angular Symmetrical Components for Voltages (Line and Phase) are introduced in this blog. Now, It is applied to currents for simplification and extraction of sequence currents. A. Star Effective Line Currents (SELC): Quadratic Mean (RMS) of all Sequence Currents is referred as "Star Effective Line Current (SELC)". This Current is equal to the Quadratic Mean of all Line Currents. The power in unbalanced star connected system will be equal to the same delivered by balanced three phase system of "SEL Current". B. Delta Effective Line Currents (DELC): Effective magnitude of Positive and Negative Sequence currents is referred as "Delta Effective Line Current (DELC)". This current is equal to effective magnitude of Delta currents / Virtual Delta Currents.  C. Earth Tangent Angle for Currents (ETAC)   The Geometric angle (as shown in figure) between SELC and DELC represents the Zero sequence current which is related to Neutral current. S...

Tangent Angle of Unbalance (TAU) - Angular form of Voltage Unbalance

   Definition: Arc Tangent of Voltage Unbalance factor (Ratio between Negative Sequence Voltage and Positive Sequence Voltage) Estimation of TAU 1. Using Two Voltages and Phase Angle Differences              Let the two voltages are Vab, Vbc and Phase angle between these two voltages in Positive Sequence direction δ, Then the voltage unbalance factor will be determined as follows. 2. Using Phase Angle Differences Let the three phase angle differences are δ 1 , δ 2  and δ 3 3. Using three Voltage magnitudes Let the Three Line voltages are Vab, Vbc and Vca Then we determine, Where, the factor β is referred as Voltage Biquadrate (VBR) In section 3, the magnitudes are always positive and angle independent, so the value of TAU is obtained from 0 0  to 45 0 .

NAC which combines two accreditation body NAAC and NBA

NAC stands for National Accreditation Council. It is a newly introduced accreditation system in India aligned with the National Education Policy (NEP) 2020. The NAC is part of the reforms in the higher education sector aimed at transforming regulation, accreditation, funding, and academic standards by establishing the Higher Education Commission of India (HECI) and its four constituent bodies, including the NAC. This council plays a vital role in revolutionizing the accreditation process to ensure quality and standards in higher education institutions in India moving forward, complementing existing bodies like NAAC and NBA. epravesh ​ If you were referring to NAAC by typing "NAC," the full form of NAAC is the National Assessment and Accreditation Council, an autonomous institution under UGC established in 1994 that assesses and accredits higher education institutions in India on multiple quality parameters. NAAC grades institutions on an 8-point scale and focuses on overall ...