Table of Contents

- 1 What is GMR in inductance?
- 2 Is geometric mean distance GMD the same as geometric mean radius GMR?
- 3 What is geometrical mean radius GMR .explain its role in calculation of line inductance?
- 4 What is meant by self GMD and mutual GMD?
- 5 What is the value of GMR R ‘) Mcq?
- 6 What is the GMR of a conductor of radius r?
- 7 What is the difference between GMR and GMR for each phase?

## What is GMR in inductance?

Mutual GMD : GMD stands for Geometrical Mean Distance and is denoted by Dm. The introduction of the term mutual GMD simplifies the mutual inductance calculations between the spaced conductors. Actually, the mutual GMD represents the geometrical mean distance from one conductor to the other.

## Is geometric mean distance GMD the same as geometric mean radius GMR?

GMD & GMR stands for Geometrical Mean Distance and Geometrical Mean Radius. In GMD we take the Geometrical Mean of distances between the strands of two Transmission Lines while in GMR, Geometrical Mean of distances between the stands of a single composite conductor are calculated.

**What is GMR geometric mean radius?**

Geometrical Mean Radius GMR is basically the Geometric Mean of distances between the strands of a conductor. It is the fictitious radius of a conductor having no internal flux linkage but only external flux linkage.

**What is the utility of the geometric mean radius of the bundle conductor?**

It also reduces voltage gradient, corona loss, radio interference, surge impedance of the transmission lines. By making bundle conductor, the geometric mean radius (GMR) of the conductor increased. As the self GMR of the conductor increases, the inductance of the conductor decreases.

### What is geometrical mean radius GMR .explain its role in calculation of line inductance?

Geometrical Mean Radius GMR is basically the Geometric Mean of distances between the strands of a conductor. It is the fictitious radius of conductor having no internal flux linkage but only external flux linkage.

### What is meant by self GMD and mutual GMD?

The use of self geometrical mean distance (abbreviated as self-GMD) and mutual geometrical mean distance (mutual-GMD) simplifies the inductance calculations, particularly relating to multi conductor arrangements. The symbols used for these are respectively Ds and Dm.

**What is the significance of bundled conductors?**

A bundled conductor reduces the reactance of the electric transmission line. It also reduces voltage gradient, corona loss, radio interference, surge impedance of the transmission lines. By making bundle conductor, the geometric mean radius (GMR) of the conductor increased.

**What is the effect of using bundled conductors on line inductance?**

Bundling of conductors leads to reduction in line inductance. The voltage regulation of the line is also increased as the reactance of the line is reduced.

#### What is the value of GMR R ‘) Mcq?

Explanation: Bundled conductors cause the GMR to increase and thus reducing the inductance. Explanation: It is 0.7788r in the equivalent network configuration.

#### What is the GMR of a conductor of radius r?

GMR = e-1/4xr = 0.7788r Thus Geometric Mean Radius GMR of a conductor is that fictitious radius which do not has any internal flux linkage but only have external flux linkage. GMR of a conductor of radius r is given as GMR = 0.7788r

**What is the difference between GMR L and C in ACSR?**

Subscript L is used for GMR of inductance calculation and subscript C for capacitance. In above calculation for GMR L the conductor is circular of radius r. But in actual practice ACSR conductors are mostly used, so for inductance calculation r’ is replaced by D s as supplied by the manufacturer of ACSR conductor.

**What is the use of GMD and GMR in power system?**

GMD & GMR stands for Geometrical Mean Distance and Geometrical Mean Radius. This concept is very useful in Power System for the calculation of Inductance and Capacitance of Transmission Line. Why is high voltage AC used in power transmission lines instead of DC and/or higher current?

## What is the difference between GMR and GMR for each phase?

GMR is calculated for each phase separately. Each of the phases may have different GMR values depending upon the conductor size and arrangement. GMR is to be calculated when each phase is comprised of more than one conductor per phase as in the example above.