What are the implications of connecting different vector group like Dyn11 and Dyn5 distribution transformer in a network?

A Dyn11 and a Dyn5 have different vector groups so they can’t be paralleled directly by matching busings. However, using two phase rolls and different bushing connections, the vector groups can be matched.

First, here are the vector groups for a Dyn1, Dyn5 and Dyn11 when excited by counter clockwise, positive sequence, phase rotation ABC:

Note that the vector groups for the Dyn1 and Dyn5 are in phase with each other but the bushings don’t match—the Dyn5 lags the Dyn1. Also note that the output vector group of a Dyn1 lags a Dyn11 by 60º.

Here is where it gets interesting. When the phase rotation of the excitation source is reversed from ABC to ACB, the vector groups are mirrored as shown below (a phase rotation meter connected ABC would rotate in the negative direction; or if connected ACB, would rotate in the positive direction):

When these two sets of vector groups are compared, it becomes apparent that a Dyn11 vector group can be matched to a Dyn5 provided one of them has reverse phase rotation. There are two possible combinations.

Given a Dyn11 with positive sequence phase rotation ABC, a Dyn5 will have the same vector group if the phase sequence is rolled:

Can you see how to parallel these? The bushing match is A-A, B-C, C-B, a-c, b-b, c-a.

The second combination is derived by taking the Dyn5 as the reference. Given a Dyn5 with positive sequence phase rotation ABC, a Dyn11 will have the same vector group if the phase sequence is rolled:

The bushing match is the same: A-A, B-C, C-B, a-c, b-b, c-a.

So there are the implications of matching the vector groups of a Dyn11 and Dyn5. Now, please read the following disclaimer.

DON’T TRY TO PARALLEL YOUR TRANSFORMERS UNLESS YOU HAVE VERIFIED FOR YOURSELF THAT THE VECTOR GROUPS WILL MATCH.

WHEN YOU THINK YOU HAVE A MATCH, HAVE YOUR WORK VERIFIED.

MAKE SURE YOU USE PHASING STICKS TO MEASURE AND VERIFY THAT ALL VECTORS MATCH BEFORE CLOSING THE PARALLELING BREAKER.

USE A PHASE ROTATION METER TO VERIFY PROPER PHASE ROTATION FOR EACH TRANSFORMER BEFORE CLOSING THE PARALLELING BREAKER.

REMEMBER TO TAKE YOUR TIME AND BE SAFE!

What does Dyn11 mean on a transformer?

Dyn11 is vector group notation of tansformer.It means LV winding,

which is star connected (written in small letters means LV side and vice versa)is 30 degrees lagging by HV winding which is delta connected.

D = Delta connection at primary,y = Star connection at secondary and n = neutral point connected at secondary. 

Dyn 11 means that the voltage of the secondary star winding lead the primary phase voltage by 30 degree and it corresponds to 11 o'clock. 

Having a background in electrical engineering, you must know all types of electrical transformer symbols. 

A transformer is an electrical machine(called in electrical engineering) or passive component(called in electronics engineering)

 that transformer electrical energy from one circuit to another circuit with the help of faraday's law of electromagnetic induction. 

In this article, we are going to see the symbol of transformer. 

Single Phase Transformer Symbol

Here, you can see the symbol of a single phase transformer.

This symbol is used for single-line wiring diagrams. So, you must know this transformer's single line diagram symbol. 

Here, the two circles indicate the two winding of the transformer. 

These two circles are overlapped to each other because it indicates they are wound on the same core and magnetically connected to each other.

 The upper and lower two lines indicate the primary and secondary winding terminals of the transformer.

Three Phase Transformer Symbol

Here, you can see the symbol of a three-phase transformer.

It is also almost the same as the single-phase transformer, just the difference is here, 

three lines on both sides that indicate the three-phase terminals of the transformer.

Iron Core Transformer Symbol

Based on the core material Transformer is classified into main three types. 

Iron Core Transformer is one of them. Here, you can see the symbol of Iron Core Transformer.

Ferrite Core Transformer Symbol

It also comes under the types of transformer classified based on the core material.

Air Core Transformer Symbol

Here, you can see the symbol of Air Core Transformer

Variable Transformer Symbol

Variable Transformer is that where voltage can be varied either by providing tapings or changing the position of the transformer core.

Step Down Transformer Symbol

Here, you can see the symbol of step down transformer.

Step Down transformer transfers the electrical energy by lowering the voltage and increase the current.

 A step down transformer has more turns in primary winding than the secondary winding. 

So, you can see the turns difference in primary and secondary winding in its symbolic diagram.

Step Up Transformer Symbol

Step Up transformer increases the voltage but decreases the current in its secondary side.

 Step Up transformer has fewer turns in primary winding than its secondary winding.

Autotransformer Symbol

Here, you can see the symbol of autotransformer. An autotransformer has a single winding. 

Tapping is provided for the output power supply.

IsolationTtransformer Symbol

Here, you can see the symbol of Isolation transformer. 

The isolation transformer is that where both primary and secondary winding has the same turns and they carry the same voltage also. 

The isolation transformer is used where proper isolation is required between two different power circuits.

CT or Current Transformer Symbol

It is an instrument transformer. Current transformer mainly used for measurement purpose, automation purpose, etc.

PT or Potential Transformer Symbol

Here, you can see the symbol of potential transformer. 

It is also an instrument transformer and used for measurement and control systems.

Symbol of Voltage Transformer

The voltage transformer is used everywhere such as power transformer, distribution transformer, etc.

AC Transformer Symbol

Power Transformer Symbol

Power transformers are used in power generating stations. 

The main function of the power transformer is to step up the voltage for high voltage power transmission.

 Power transformers are generally, Star-Delta connected, 

which means they have star-connected winding in the primary side and delta-connected winding in the secondary winding. 

Here, you can see the symbol of power transformer.

Distribution Transformer Symbol

Distribution transformers are used on the consumer end.

 The main function of the distribution transformer is to step down the voltage if required and distribute the electrical power with an electrical balance. 

Generally, distribution transformers are Delta-Star connected, but they may be Star-Star connected also.

 Here, you can see the symbol of Distribution Transformer.

A transformer is an electrical device that uses the principle of electromagnetic induction to 

transfer energy from one electric circuit to another. It is designed to either increase or decrease 

AC voltage between the circuits while maintaining the frequency of the current.

· Power Transformers. A power transformer transfers electricity between a generator and the distribution primary circuits. ...

· Auto transformers. Now, let's make things even more complicated. ...

· Generator Step-Up Transformers. Moving right along to GSUs or generator step-up transformers. ...

· Auxiliary Transformers.

A transformer cannot convert AC to DC or DC to AC. The transformer has the ability to step up or decrease current. A step-up transformer is a transformer that raises the voltage from the primary to the secondary

When a d.c voltage source is applied across the primary of the transformer,the current in the primary coil remains constant. Hence there is no change in the magnetic flux linked with the secondary. Therefore the voltage across the secondary coil is zero. Thus a transformer can't step up dc voltage.

Transformers only work on alternating current (a.c.). The current in the primary coil causes it to become an electromagnet. The continually changing current produces a continually changing magnetic field in an iron core.