To protect large electrical system from overload or to monitor large current loads by means of a metering instrument Current Transformer plays a very important role. It provides the necessary tools to capture the actual load current and reduces its values by means of transformation ration to a minimum of safe value. Therefore, selection of accurate and reliable current transformers are very crucial.
SES range of metering, measuring and protective current transformers are designed and manufactured to cater for wider range of applications. They are tested to IEC60044-1 2003-02 and are certified to ASTA & CE Mark Certified to UL.
Application guide to accuracy class
Accuracy Class
Application
0.1
Precision Testing or as a standard for testing other CTs
0.2
Precision Metering
0.5
General Tariff Metering
1.0
Non Revenue measurement incl. power and energy
3.0
General industrial measurement
5.0
Approximate measurement
Table – limit of current error and phase displacement for measuring current transformer (class 0.1 to 1)
Accuracy Class
± Percentage current (ratio) error at percentage of rated current shown below
± Phase displacement at percentage of rated current shown below
Minutes
Centiradians
5
20
100
120
5
20
100
120
5
20
100
120
0.1
0.4
0.2
0.1
0.1
15
8
5
5
0.45
0.24
0.15
0.15
0.2
0.75
0.35
0.2
0.2
30
15
10
10
0.9
0.45
0.3
0.3
0.5
1.5
0.75
0.5
0.5
90
45
30
30
2.7
1.35
0.9
0.9
1.0
3.0
1.5
1.0
1.0
180
90
60
60
5.4
2.7
1.8
1.8
Table – limit of current error and phase displacement for special application
Accuracy Class
± Percentage current (ratio) error at percentage of rated current shown below
± Phase displacement at percentage of rated current shown below
Minutes
Centiradians
1
5
20
100
120
1
5
20
100
120
1
5
20
100
120
0.2s
0.75
0.35
0.2
0.2
0.2
30
15
10
10
10
0.9
0.45
0.3
0.3
0.3
0.5s
1.5
0.75
0.5
0.5
0.5
90
45
30
30
30
2.7
1.35
0.9
0.9
0.9
Table – limit of current error and phase displacement for measuring current transformer (class 3 to 5)
Accuracy Class
± Percentage current (ratio) error at percentage of rated current shown below
50
120
3
3
3
5
5
5
Limits of phase displacement are not specified for class 3 and class 5.
Table – limit of current error for protection current transformer
Accuracy Class
Current error at Rated primary current %
Phase displacement at rated primary current
Composite error at rated accuracy limit primary current %
The Burden imposed on Current Transformer consist mainly of the following:- a) The impedance of the relays of instruments. b) The impedance of pilot wire between current transformer and relay or instruments. c) The sum of (a) & (b) consitute the external burden required.
Enquiry / Ordering Information 1. When enquiring or ordering, please specify the following: a) Ration : 30 / 5A to 6000 / 5A 20 / 1A to 6000 / 1A b) Class : 0.2, 0.5, 1, 3.5 c) Burden (VA) : 2.5, 5, 10, 15, 20. d) ALF for Protective C/T : P5, P10, P15, P20.
2. For non-standard sizes, please provide additional informations such as:- a) Internal Diameter required in mm(D) b) Outer Diameter required in mm(OD) c) Height required in mm (HT) d) Rated secondary current if other than 5A
Safety Precautions! The secondary terminals when not in used must be shorted before the primary supply is energised. Otherwise high voltage will develop across the secondary terminals causing damage to the current transformer and danger to life.
Note: All specification are subject to change without prior notice for product improvement. Images, pictures, and illustrations used are for illustrative purposes only and the color printed in the brochure may differ from the actual product.
Summation CT
Description
Summation CT
DownloadTo protect large electrical system from overload or to monitor large current loads by means of a metering instrument Current Transformer plays a very important role. It provides the necessary tools to capture the actual load current and reduces its values by means of transformation ration to a minimum of safe value. Therefore, selection of accurate and reliable current transformers are very crucial.
SES range of metering, measuring and protective current transformers are designed and manufactured to cater for wider range of applications. They are tested to IEC60044-1 2003-02 and are certified to ASTA & CE Mark Certified to UL.
Specifications
Burden Requirements
The Burden imposed on Current Transformer consist mainly of the following:-
a) The impedance of the relays of instruments.
b) The impedance of pilot wire between current transformer and relay or instruments.
c) The sum of (a) & (b) consitute the external burden required.
Enquiry / Ordering Information
1. When enquiring or ordering, please specify the following:
a) Ration : 30 / 5A to 6000 / 5A
20 / 1A to 6000 / 1A
b) Class : 0.2, 0.5, 1, 3.5
c) Burden (VA) : 2.5, 5, 10, 15, 20.
d) ALF for Protective C/T : P5, P10, P15, P20.
2. For non-standard sizes, please provide additional informations such as:-
a) Internal Diameter required in mm(D)
b) Outer Diameter required in mm(OD)
c) Height required in mm (HT)
d) Rated secondary current if other than 5A
Safety Precautions!
The secondary terminals when not in used must be shorted before the primary supply is energised. Otherwise high voltage will develop across the secondary terminals causing damage to the current transformer and danger to life.
Note: All specification are subject to change without prior notice for product improvement.
Images, pictures, and illustrations used are for illustrative purposes only and the color printed in the brochure may differ from the actual product.