Recent Blog Entries

  •     Power distribution systems used in large commercial and industrial applications can be complex. Power may be distributed through switchgear, switchboards,  transformers, and panelboards. Power distributed throughout a commercial  or industrial application is used for a va...
  •       CONVENTIONAL INCOMER   The devices used in the incomer should be capable of: Switching and carrying normal currents (generally above 1200 A); Withstanding abnormal currents for a short duration in order to allow downstream devices to operate; Interrupting the max...
  •   K-factor transformers are designed to be able to be used for loads with harmonic distortion without the necessity of de- rating. If a K-factor transformer is to be used in an application it is necessary to know the load characteristics and the harmonic content over the whole load cycle and...
  • Power Factor Improvement If the power factor is low or poor, it is necessary to improve or correct it. It may be improved by injecting a leading current into the circuit so as to neutralize the effect of lagging current. The power factor may be improved ...
View All

Main and Transfer Bus

  • A main and transfer bus configuration consists of two independent buses, one of which, the main bus, is normally energized. Under normal operating conditions, all incoming and outgoing circuits are fed from the main bus through their associated circuit breakers and switches. If it becomes necessary to remove a circuit breaker from service for maintenance or repairs, the integrity of circuit operation can be bus tie equipment. The bypass switch for the circuit breaker to be isolated is closed, the bus tie breaker and its isolation switches are closed, and the bypassed breaker and its isolation switches are opened to remove the breaker from service. The circuit is then protected by the bus tie breaker.

     

    Figure   illustrates a main and transfer bus configuration in a low-profile arrangement. For comparison, Figure   shows the same switching scheme with high-profile box-type structures. With the box-type structure arrangement, two circuit positions can be accommodated per equipment bay. However, with the low-profile arrangement, each circuit requires its own bay and, as a result, somewhat more land area may be required. When the low-profile configuration is used, equipment bays should be limited in width to a maximum of two bays before the bay-tobay centerline spacing is increased to accommodate circuit breaker maintenance and removal. Without the additional space these tasks can become very difficult.

     

    The high-profile, box-type structure arrangement shown in Figure   can accommodate multiple circuits in a relatively small area. The configuration is particularly suitable in environmentally shielded or otherwise isolated locations, where only a limited substation site is available. This arrangement is generally limited to distribution and sub-transmission voltage levels. At transmission voltage levels, independent structures and strain bus interconnections can be used.

     

    Advantages: 

    • Accommodation of circuit breaker maintenance while maintaining service and line protection 
    • Reasonable in cost
    • Fairly small land area
    • Easily expandable

     

    Disadvantages:

    • An additional circuit breaker is required for bus tie.
    • Since the bus tie breaker, have to be able to be substituted for any line breaker, its associated relaying may be somewhat complicated.
    • Failure of a circuit breaker or a bus fault causes loss of the entire substation.
    • Somewhat complicated switching is required to remove a circuit breaker from service for maintenance.

    Reference:

Comments

3 comments
  • Fouzi Eshtewi and Davis Keith like this
  • Kip Gallo
    Kip Gallo Accept my friendship
    Apr 20
  • Leigh Keeney
    Leigh Keeney Good Share
    Jun 9
  • Lilla Silvia
    Lilla Silvia #Rules of the collisions....where these people obtain their licenses? biggest concern is lack of seamanship so are companies really aware on who is working on their vessels?
    Nov 9

What's New

No results found!