Supply and Installation of Industrial Fan for Ventilation System and Grounding System Design for Electric
Static Discharge for Chemical Charter and Coating Corporation located at Mercedez Ave. Pasig City
Friday, March 31, 2017
Sunday, September 18, 2016
Plant Design: Motor Protection Parameters
The table below is an example of a working protection parameters of an electrical system. A parameter sheet such as this will enable the designer to tabulate necessary initial values and calculations.
First is to work out in calculating the circuit current of a three phase motor circuit:
Circuit Current=kW/(√3∗kV∗pf )
Instrument and protection CTs are governed by standard IEC 60044-1 . The matching of CTs with protection relays calls for a thorough knowledge of CTs. The following section gives a few reminders in determining the CT ratio, the table below will give the recommended primary CT ratio for various circuit current in the motor protection section. See (link) for complete list of CT ratio per application.
CT Primary=kW/(√3∗kV∗pf *η )
If you do not know exact values for ϕ and η as a first approximation, you can assume that: cos ϕ = 0.8 ; η = 0.8. T. The secondary circuits of a CT must be suitable for the constraints related to its application for or protection purposes.
CT Secondary
For use in a local situation Isn = 5 A
For use in a remote situation Isn = 1 A
The use of 5 A in a remote situation increase the cross section of the line or the sizes of the transformer (lost in line). IEEE C57.13 Table 8 - Standard multi-ratio current transformer taps gives the standard ratings for instrument transformers. Sequence CT Ratio are constant 100/1 in 4.160 and 6.9kV Circuit.
For the circuit Type in 6.9kV , there are two recommended circuit types. Use Vacuum Circuit when the Current reached above 100 Amps or Fused Contractor when dealing with currents below 100 Amps.
NO.
|
Equipment
name
|
Nominal
power
(kW)
|
Circuit
calculation current(A)
|
CT
trans. ratio
|
Zero
sequence CT trans. ratio
|
Circuit
type
|
1
|
Motor Pump No.1
|
3400
|
355.6
|
1000/1
2000/1(Differential)
|
100/1
|
Vacuum
breaker
|
2
|
Motor Pump No.3
|
1400
|
146.4
|
500/1
|
100/1
|
Vacuum
breaker
|
3
|
Motor Pump No.3
|
1000
|
104.6
|
400/1
|
100/1
|
Vacuum
breaker
|
4
|
Motor Pump No.4
|
400
|
41.8
|
200/1
|
100/1
|
F-C
circuit
|
5
|
Motor Pump No.5
|
900
|
94.1
|
300/1
|
100/1
|
F-C
circuit
|
6
|
Motor Pump No.6
|
710
|
74.3
|
200/1
|
100/1
|
F-C
circuit
|
First is to work out in calculating the circuit current of a three phase motor circuit:
Circuit Current=kW/(√3∗kV∗pf )
Instrument and protection CTs are governed by standard IEC 60044-1 . The matching of CTs with protection relays calls for a thorough knowledge of CTs. The following section gives a few reminders in determining the CT ratio, the table below will give the recommended primary CT ratio for various circuit current in the motor protection section. See (link) for complete list of CT ratio per application.
CT Primary=kW/(√3∗kV∗pf *η )
If you do not know exact values for ϕ and η as a first approximation, you can assume that: cos ϕ = 0.8 ; η = 0.8. T. The secondary circuits of a CT must be suitable for the constraints related to its application for or protection purposes.
CT Secondary
For use in a local situation Isn = 5 A
For use in a remote situation Isn = 1 A
The use of 5 A in a remote situation increase the cross section of the line or the sizes of the transformer (lost in line). IEEE C57.13 Table 8 - Standard multi-ratio current transformer taps gives the standard ratings for instrument transformers. Sequence CT Ratio are constant 100/1 in 4.160 and 6.9kV Circuit.
For the circuit Type in 6.9kV , there are two recommended circuit types. Use Vacuum Circuit when the Current reached above 100 Amps or Fused Contractor when dealing with currents below 100 Amps.
Sunday, September 4, 2016
Power System Study for CADPI
Our freelancer have been involved in the Analysis of Electrical System of Central Azucarera De Don Pedro (CADPI) in Nasugbu , Batangas Philippines. The scope of the projects includes Short Circuit Analysis, Load Flow and Protective Device Coordination evaluation of the Plant.
Electrical Designs for Penthouse in Baguio City
Electrical Design for 4 Storey Residential/Commercial Building with Roof deck, Villanueva Residence-2 Storey Residential with Penthouse (Baguio City) and Manager’s Project : 2 Storey with Penthouse (Baguio City) . This is still on going project
Electrical Design Projects in USA
Our freelancer have handled major electrical design projects for clients in USA. Among these projects are design contracts under MR Engineering Consultants:
1. RECOVERY CAFE-FIRST CHRISTIAN CHURCH
80 South 5th Street, San Jose CA 95112
2.HOTEL CLARIANA-5 Storey Commercial Building
100 East Sta. Clara, & 10S 3rd St. San jose CA. 95113
3.North Bascom- Medical Office
105 North Bascom Ave. #100 & 101 San Jose CA
4. Elite Educational Institution
155 Anza St. Fremont CA
5. St. Martin of Tours
200 O' Conner Dr. San Jose CA
1. RECOVERY CAFE-FIRST CHRISTIAN CHURCH
80 South 5th Street, San Jose CA 95112
2.HOTEL CLARIANA-5 Storey Commercial Building
100 East Sta. Clara, & 10S 3rd St. San jose CA. 95113
3.North Bascom- Medical Office
105 North Bascom Ave. #100 & 101 San Jose CA
4. Elite Educational Institution
155 Anza St. Fremont CA
5. St. Martin of Tours
200 O' Conner Dr. San Jose CA
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