The document provides information on training goals and electrical distribution equipment including transformers, switchgear, generators and breakers. It discusses the characteristics and functions of transformers, switchgear, breakers, substations and emergency generators. Diagrams of one-line diagrams and typical electrical symbols are shown. Procedures for restoring power during different loss of power scenarios are outlined.

1. POWER DISTRIBUTION
TRAINING

2. GOALS OF TRAINING
Electrical Distribution Equipment
Transformers, Switch Gear, Gen., Breakers)
One-line Diagram Interpretation
•Hands-on Application
•Restoring Power

3. What is a Transformer?
NO YES

4. CHARACTERISTICS OF A TRANSFORMER
•A transformer is a static device which transforms electrical power from
one voltage or current level to another keeping the same frequency
through electromagnetic induction.
•A varying current in the transformer's primary winding creates a
varying magnetic flux at the secondary induces a varying electromotive
force or voltage in the secondary winding.

5. High Voltage Transformers Characteristics
•Steps primary voltage (28KV) down on the secondary voltage (4160V)
•Oil inside of these transformers acts as a cooling agent to reduce heat
•Nitrogen is applied to transformers to remove oxygen and water

6. Medium Voltage Switchgear
•Combination of electrical disconnect
switches, fuses or circuit breakers used to
control, meter, protect and isolate electrical
equipment
•Has a main breaker that applies the
secondary voltage (4160V) to bus lines
upon closing
•Has two incoming feeds separated by a tie-
breaker.

7. Breaker Function
•The main function of a breaker
is to connect/disconnect to or
from a bus line upon
closing/opening.
•They also have a protective
feature of opening or “tripping”
on high currents
•Although there are various
types of breakers (air or
vacuum) the function remains
the same.

8. Substations & Motor Control Centers
Have a transformer to step the primary
voltage (4160V) down to the secondary
voltage (480V)
An assembly of one or
more enclosed sections
having a common
power bus

9. Emergency Generators
•Diesel powered systems that generate their own power to be applied
to switchgear automatically in the event of full power loss
•Have a peak shaving component that aids in power consumption
reduction

10. ONE-LINE DIAGRAMS
A line diagram is used to show the
relationship between circuits and their
components but not the actual location
of the components

11. TYPICAL ELECTRICAL DRAWING SYMBOLS

13. Simple One-Line Diagram
Schematic

14. Loss of Power Scenarios
Scenario: A plant with 2 transformers has the
motor load evenly distributed. No bus ties are
closed.

15. There is a loss of power on transformer 1. What
happens?
There is a power loss on 1 and 2
transformers. What happens?
The breaker feeding one side of
the substation fails open. What
happens?

16. Controlled Shutdown
In the event of an scheduled shutdown of one or
more primary transformers, what are some of
the procedures that need to be followed?

17. 1. First unload affected
switchgear bus by
removing pumps from
service and tying
substation feeds to
provide for
uninterrupted service as
needed.
3. Remove control fuses
2. Open main
breaker from
control panel
remote switch
Remove control
fuses
4. For further
isolation breaker
may be lowered
and removed from
cabinet.

18. BREAKERS
A circuit breaker is an automatically operated electrical switch designed
to protect an electrical circuit from damage caused by overload or short
circuit. Its basic function is to detect a fault condition and interrupt
current flow.

19. The circuit breaker which operates in air at atmospheric pressure. For
interrupting arc it creates an arc voltage in excess of the supply voltage.

20. Vacuum Circuit Breakers
These breakers interrupt the current
by creating and extinguishing the arc
in a vacuum container - aka "bottle".
Long life bellows are designed to
travel the 6-10 mm the contacts must
part. Vacuum circuit breakers tend to
have longer life expectancies between
overhaul than do air circuit breakers

21. Oil Circuit Breakers
The oil is used to insulate between the phases and between the phases
and the ground, and to extinguish the arc. When electric arc is drawn
under oil, the arc vaporizes the oil and creates a large bubble of
hydrogen that surrounds the arc. The oil surrounding the bubble
conducts the heat away from the arc and thus also contributes to
deionization and extinction of the arc.

22. Purpose of Main/Tie Breakers/Interlocks
The tie breaker system is designed only to have one transformer
operating when the tie breakers are closed, or in other words the
system is not intended to run with the utility transformer paralleled.
Interlock systems are in place to ensure that the ties and both mains are
never all closed at once putting transformers in parallel.

23. Typical Tie-Breaker with
Interlocks

24. Difference Between Breakers for Medium
Voltage and Substations
Substations transform voltage from
high to low, typically 4160V to 480V,
and operate under the same
governing principles as medium
voltage switchgear.
Switchgear is the combination
of electrical disconnect
switches, fuses or circuit
breakers used to control,
protect and isolate electrical
equipment loads of 4160V

25. Open Transition Breaker
It prevents back feeding from an
emergency generator back into
the utility line

26. Closed Transition
synchronization : voltage difference
less than 5%, frequency difference
less than 0.2 Hz, and maximum phase
angle between the sources of 5
electrical degrees

27. Raking in and out of Breakers
Racking provides a method of
isolating a high-voltage
metal-clad circuit breaker
from its supply and load
circuits, and/or to provide
grounding. Before racking,
the circuit breaker must be
opened, and this is usually
ensured using an interlock
system.

29. RESTORING POWER
1. Knowledge of Procedure
2. Response Time
3. Contacting Effected
Parties
4. Investigating the Cause
5. Waiting for Stability

30. Restoring Power Scenarios
There is a loss of power on
transformer 1. How do you restore
power?
There is a power loss on 1 and 2
transformers. How do you
restore power?
The breaker feeding one side of
substation 1 fails open. How
do you restore power?

31. Southwest Procedures
If under normal operations, either Transformer 1 or 2 has lost power:
1. Look at the control board to determine which transformer has been lost.
2. Close the trip/close switch for the tie breaker so that transformer 1 powers up bus1 and
bus 2 and trip the trip/close switch for transformer 2 or
3. Close the trip/close switch for the tie breaker so that transformer 2 powers up bus 1 and
bus 2 and trip the trip/close switch for transformer 1(depending on which transformer has
been lost).
4. If no high lift pump is in service due to the power loss, start a high lift pump as soon as
possible to restore system pressure.
5. Notify systems control and the senior chemist that there has been a loss of power and
request their preference as to which pumps should be put in service so that adjustments
can be made.
6. Put the desired high lift and low lift pumps in service.
7. The sr. operator, operator and sr. chemist will coordinate to restart all equipment and
machinery that may have been affected by the power loss.
8. Be sure to do a trouble report so that the emergency can be documented.

32. Response Time
It is critical to react safely, competently
and quickly to power loss events. Being
aware of what power source is
supplying equipment in service, and
relying on your team (Water Techs,
Chemist, SCC) to provide information in
cause of an loss is essential.
If possible, starting another pump to
restore system pressure is the priority
over restoring loss power.

33. Contacting DTE/SCC/Management
Notification of power loss and the current
status is crucial during a power loss event.
Contact numbers for SCC and DTE should be
posted or readily available.
Notification of management and detailed
documentation of what occurred and the steps
taken to restore power are also important.

34. Troubleshooting Power Loss
After restoring system
pressure and establishing a
power source, the next step is
to investigate the potential
causes of the power loss.
Although you are not an electrician, detailed notes of what has taken
place during the event are necessary for the maintenance crew to find
the cause and repair or replace any damaged equipment.

36. Following Proper Procedures/Waiting for
Stability
Before normal power
distribution operation
can be restored, a high
probability of stability
must be known.
Helps to avoid a repeat
of the power loss.
Working with DTE or
the maintenance crew
to establish cause will
provide insight
You are the first line of
defense in protecting
the public.

37. Test Time