🔌 Match the Basic Notions with Their Polish Equivalents

based on the lecture "Quantities and units used in electrical engineering" by dr hab. inż.. Andrzej Waindok, prof. PO

adapted by mgr Bożena Hordyńska

Three-phase circuits - reading & definitions

📚Read the text below and do the task below.

Basic Information about

Three-phase Circuits

Almost all power systems are based on three-phase circuits. In the energy

sector, three-phase generators, transformers, and transmission lines are

commonly used.

A polyphase system

is a set of electrical circuits in which

sinusoidal source voltages of the same frequency operate, shifted in phase

relative to each other and usually generated in a single power source called a

If the phases of a polyphase system are not galvanically connected, the

system is called

The voltages generated in a polyphase system form a symmetrical system

when all phases have equal effective (or maximum) values and are shifted

relative to each other by the same angle.

     This system is called a positive-sequence symmetrical system

because, assuming a counter clockwise direction of rotation, the phase sequence

is

 Symmetrical System:

• The effective value and angular frequency of the

  source voltage in each phase are the same.

• The load impedance in each phase is the same.

• There is a phase shift of ± (2π/m) (120º) between

  the phases.

An asymmetrical system

occurs when any of these conditions are not

met.

Types of Three-phase Systems

Three-phase systems are most commonly connected in a star (Y) or

delta

(Δ) configuration

The following notations are used:

• I_A, …

  – Line

  currents

• I_AB, …

  –

  Phase currents

• U_A, … E_A

  –

  Phase voltages

• U_AB, …

  –

  Line-to-line voltages

• I_N

  – Current in the neutral

  or zero conductor

based on the lecture: 'Three-phase Circuits' by dr hab. inż. Andrzej Waindok, prof. PO

adapted by mgr Hanna Kośmider- Matwiejczuk

Match the key terms with their

correct definitions: