Wêjeya Tirîfik: Amûra Serkeftinî yên Analîzda Çewtiyên Têknicî
A transformer û û ekezê dike ku hûn elektrîkî energy ji her sîstema din derve bi electromagnetic induction. Transformers zafereyên digireyên bikaranîn da di power systems de bi rêjiya step up an step down voltages, isolate circuits, and balance loads. Transformers dikarin biguherînin ji bo navên yekbûyên ji bo construction, winding configuration, and vector group.
A vector diagram ya transformer û ekezê grafik a niha dike ku phasor relationships nîşan dide yên di primary û secondary voltages û currents ya transformer. Ekezê tool a bêtir ye ji bo fahm performance û behavior ya transformer ji bo seroperên different operating conditions û fault scenarios.
Di vê article de, ew ê we têxin bêje mîna vector diagram ya transformer, ji bo çawa drawing, û ji bo çawa use it for fault analysis. We also discuss the different types of transformer connections and vector groups and their implications for power system protection and coordination.
What is a Vector Diagram?
A vector diagram û ekezê diagram a niha dike ku one or more vectors can be represented. A vector û ekezê quantity a niha ku hemî magnitude û direction heye. In electrical engineering, alternating quantities such as voltages û currents are often represented by vectors, because they vary in magnitude û direction with time.
On a vector diagram, alternating quantities are represented by arrows. The length of the arrow represents the rms value of the alternating quantity. The angular position represents the phase angle of the quantity with respect to a reference axis or another quantity. The arrowhead represents the direction in which the quantity is acting.
When an electrical quantity acts away from the source towards the load, the vector representing the quantity is considered positive. When it acts towards the source from the load, it is considered negative.
What is a Vector Diagram of a Transformer?
A vector diagram of a transformer û ekezê vector diagram a niha dike ku phasor relationships nîşan dide yên di primary û secondary voltages û currents of a transformer. It also shows the phase shift û polarity of the transformer windings.
A vector diagram of a transformer can be drawn for any type of transformer, such as single-phase or three-phase, star or delta connected, or with different winding configurations and vector groups.
A vector diagram of a transformer can help us to:
Determine the equivalent circuit parameters of a transformer, such as impedance, resistance, reactance, and losses.
Analyze the performance û efficiency of a transformer under various loading conditions, such as no-load, full-load, over-load, or short-circuit.
Identify û diagnose faults in a transformer or its associated circuits, such as open-circuit, short-circuit, earth-fault, or inter-turn fault.
Select û coordinate protective devices for a transformer, such as fuses, circuit breakers, relays, or differential protection schemes.
Verify the correct connection û polarity of a transformer during installation or commissioning.
How to Draw a Vector Diagram of a Transformer?
To draw a vector diagram of a transformer, we need to know the following information:
The rated voltage and current of the primary û secondary windings of the transformer.
The winding configuration û connection of the transformer, such as star or delta.
The vector group of the transformer, which indicates the phase shift û polarity of the windings.
The load impedance û power factor of the transformer.
The steps to draw a vector diagram of a transformer are:
Choose a reference axis for the diagram. Usually, the horizontal axis is chosen as the reference axis.
Draw the primary voltage vector along the reference axis with its positive direction pointing to the right. Label it as V1.
Draw the secondary voltage vector with its length proportional to its rms value û its angle according to its vector group. Label it as V2.
Draw the primary current vector with its length proportional to its rms value û its angle according to its power factor. Label it as I1. The direction of I1 should be opposite to V1 if the primary winding is supplying power to the secondary winding.
Draw the secondary current vector with its length proportional to its rms value û its angle according to its power factor. Label it as I2. The direction of I2 should be opposite to V2 if the secondary winding is receiving power from the primary winding.
Draw the load impedance vector with its length proportional to its value û its angle according to its power factor. Label it as ZL. The direction of ZL should be opposite to I2 if the load is passive (resistive or inductive).
Draw any other vectors that are relevant for analysis, such as impedance, resistance, reactance, losses, etc.
Example: Vector Diagram of a Single-Phase Transformer
Let us consider a single-phase transformer with the following specifications:
Rated primary voltage: 240 V
Rated secondary voltage: 120 V
Rated primary current: 10 A
Rated secondary current: 20 A
Winding configuration: Star-star
Vector group: Yy0
Load impedance: 6 ohms resistive
