An overload on a distribution zone substation transformer can be detected with: Select one: a. Differential...
An overload on a distribution zone substation transformer can be detected with:
Select one:
a. Differential protection
b. A top-oil temperature sensor, a winding temperature monitoring system.
c. An IDMT or instantaneous overcurrent relay
d. A Buchholtz relay.
Homework Answers
An overcurrent relay or instantaneous relay or IDMT relay can detect when very large currents flows or an overload occurs.
Hence option c is correct.
Add Answer to:
An overload on a distribution zone substation transformer can be
detected with:
Select one:
a. Differential...
A protection scheme for one of the main delta-star transformers at a zone substation features the following: differential protection; restricted carth fault protection; . Buchholz and gas impulse rel...
A protection scheme for one of the main delta-star transformers at a zone substation features the following: differential protection; restricted carth fault protection; . Buchholz and gas impulse relays; phase overcurrent protection on both primary and secondary side; earth fault protection on the secondary side; and thermal overload protection Explain the specific role the above listed protection elements in terms of the nature of the fault and the need for back-up.
A protection scheme for one of the main delta-star...
a) In reference to a single phase circuit, briefly explain the response of relay during an in-zone, and through fault co...
a) In reference to a single phase circuit, briefly explain the response of relay during an in-zone, and through fault conditions. b) Explain the four factors that reliability of a transformer is dependent upon. c) List four methods of grounding an Electrical system d) Briefly, explain with a protection diagram how phase fault and earth fault relay(s)can be used to detect a stator short circuit faults on a polyphase induction motor
A generator transformer has a magnetising current of 1.5 %. The primary winding voltage is 27 kV and the secondary voltage is 330kV. The transformer rating is 360 MVA. What is the allowable operating...
A generator transformer has a magnetising current of 1.5 %. The primary winding voltage is 27 kV and the secondary voltage is 330kV. The transformer rating is 360 MVA. What is the allowable operating current differential, in terms of Amperes on the primary, that should not cause the protection to operate? Select one: a. 200.00 Amperes b. 31.08 Amperes c. 115.47 Amperes d. 66.00 Amperes
A distribution board distributes energy to various items of plant via an installation which has a...
Step by step precise and concise full solution please
A distribution board distributes energy to various items of plant via an installation which has a high voltage (H.V.) panel, a low voltage (L.V) panel and a transformer. The details are as follows: The H.V. panel obtains a 3-phase supply at 11 kV. The transformer circuit-breaker is equipped with 75/5A current transformers which feed a very inverse 3-poles overcurrent relay of 5-A rating. The transformer has a rating of 1000 kVA...
An on load tap changer is installed on a transformer and shares the transformer tank. The tap cha...
An on load tap changer is installed on a transformer and shares the transformer tank. The tap changer mechanism and contacts and the transformer windings are in the same oil volume. Due to mechanical wear and contact oxidisation, one tap changer contact begins to get hot ( a few hundred degrees). This fault persists for months and will eventually cause the failure of the insulation on adjacent components. What protection systems or inspection procedures might detect this developing fault? Select...
A magnetisation transient can occur when a transformer is energised. The protection scheme must not unecessarily trip...
A magnetisation transient can occur when a transformer is energised. The protection scheme must not unecessarily trip the transformer by mistaking the inrush for a fault. For a large transformer the better approaches are: Select one: a. Block the protection scheme for a few seconds when the transformer is energised. b. Use a even harmonic or minimum gap time scheme. c. Time the breaker closing to reduce the inrush transient. d. Set the differential protection levels high enough so that a...
can you calculating this question and explain why? thanks A distribution network shown in Figure 3 consists of a 40-MV...
can you calculating this question and explain why? thanks
A distribution network shown in Figure 3 consists of a 40-MVA and 33/22-kV step-down transformer with a reactance of 10% and two distribution lines each having a reactance of 5 Q2. The load connected to each bus is also shown in the figure. The CO-8 overcurrent relays are used to protect the system. The time-current curve of the CO-8 relay is shown in Figure 4 on page 5. Assume that the...
help me please please answer many as possible 10. The hysteresis loss in the core of a transformer can be reduced by A. increasing the frequency of the aliemating current, B. using a solid iro...
help me please
please answer many as possible
10. The hysteresis loss in the core of a transformer can be reduced by A. increasing the frequency of the aliemating current, B. using a solid iron core. C. using grain-oriented-steel D, reducing the connected load. 11. In Fig. 1(b) in the text, the phasor I, It is the resultant of the A. exciting and the magnetizing current. B. active and the reactive secondary current. C. primary and the exciting current. D....
What is a habitable zone (the simplest definition, as used in lectures)? Select one: a. Somewhere...
What is a habitable zone (the simplest definition, as used in lectures)? Select one: a. Somewhere where liquid water could exist on a planetary surface b. A region of a planet where liquid water can exist c. A region of space where water is just able to melt d. A region of space where water can exist in all three phases.
select one Best match 11) A 12 kV radial system is given below, Assuming using relay...
select one Best match
11) A 12 kV radial system is given below, Assuming using relay CO-7, 3 cycles breaker operation time and 0.5 second coordination time delay, what are the best settings to protect the system shown below: (10 points) 12 kV Typical time curves ype Co-7 C.T.R-400/5 C.T.R-200/5 Current tap settings: 4.5,6,78,10,12 amperes 4 MVA Isc-1.6 kA 4 MVA Isc-1.2 kA Time dial TS1 TDS1 TS2 TDS2 A) 51/252 B) 41/24 C) 51/25 D) 41/24 2 4 5...
A protection scheme for one of the main delta-star transformers at a zone substation features the following: differential protection; restricted carth fault protection; . Buchholz and gas impulse relays; phase overcurrent protection on both primary and secondary side; earth fault protection on the secondary side; and thermal overload protection Explain the specific role the above listed protection elements in terms of the nature of the fault and the need for back-up.
A protection scheme for one of the main delta-star...
Step by step precise and concise full solution please
A distribution board distributes energy to various items of plant via an installation which has a high voltage (H.V.) panel, a low voltage (L.V) panel and a transformer. The details are as follows: The H.V. panel obtains a 3-phase supply at 11 kV. The transformer circuit-breaker is equipped with 75/5A current transformers which feed a very inverse 3-poles overcurrent relay of 5-A rating. The transformer has a rating of 1000 kVA...
can you calculating this question and explain why? thanks
A distribution network shown in Figure 3 consists of a 40-MVA and 33/22-kV step-down transformer with a reactance of 10% and two distribution lines each having a reactance of 5 Q2. The load connected to each bus is also shown in the figure. The CO-8 overcurrent relays are used to protect the system. The time-current curve of the CO-8 relay is shown in Figure 4 on page 5. Assume that the...
help me please
please answer many as possible
10. The hysteresis loss in the core of a transformer can be reduced by A. increasing the frequency of the aliemating current, B. using a solid iron core. C. using grain-oriented-steel D, reducing the connected load. 11. In Fig. 1(b) in the text, the phasor I, It is the resultant of the A. exciting and the magnetizing current. B. active and the reactive secondary current. C. primary and the exciting current. D....
select one Best match
11) A 12 kV radial system is given below, Assuming using relay CO-7, 3 cycles breaker operation time and 0.5 second coordination time delay, what are the best settings to protect the system shown below: (10 points) 12 kV Typical time curves ype Co-7 C.T.R-400/5 C.T.R-200/5 Current tap settings: 4.5,6,78,10,12 amperes 4 MVA Isc-1.6 kA 4 MVA Isc-1.2 kA Time dial TS1 TDS1 TS2 TDS2 A) 51/252 B) 41/24 C) 51/25 D) 41/24 2 4 5...
Most questions answered within 3 hours.
-
a radio station transmits at 78.1 mhz. a hz is an inverse
second. how far apart...
asked 4 minutes ago -
Write the equilibrium expression for the dissociation in
water for CH5N, C2H5O2COOH, H3AsO4, KClO2, HC2H2ClO2.
asked 10 minutes ago -
In risk management, insurance is an example of:
Select one:
a. Risk avoidance
b. Risk deflection...
asked 11 minutes ago -
Wildhorse Company follows the practice of pricing its inventory
at the lower-of-cost-or-market, on an individual-item
basis....
asked 46 minutes ago -
3. (10 pts) You grow a corn crop that yields 150 bushels ac-1,
with the following...
asked 34 minutes ago -
7. The term Six Sigma refers to:
Select one:
a. The control limits established in a...
asked 44 minutes ago -
For the following reaction: A(g) + 2 B(g) ⇌ 2 C(g) Calculate the
equilibrium constant K...
asked 46 minutes ago -
Which of the following best describes tidal volume? options:
1.The amount of oxygen in the air...
asked 1 hour ago -
1. Smaller cost distortions occur when the traditional systems'
single indirect-cost rate and the activity-cost-driver rates:...
asked 1 hour ago -
Using either a FMECA approach or some other appropriate RCA
tool, identify five risk treatment actions...
asked 1 hour ago -
If for a test the P-value is between 0.0025 and 0.005, what
conclusion can you draw?...
asked 1 hour ago -
Using Python. Write a function clean2(aList) that takes a list
of integers aList as argument, and...
asked 1 hour ago