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CGIS1255 Current Transformer Applied to CGIS Gas Insulated Switchgear

20kVCGIS1255

Winding & Schematic TopologyInternal Wiring Diagram

Primary Winding (P1 - P2):Series-connected in the line / through-core — 20kV

Secondary Metering (1S1 - 1S2): (0.2,0.5,1.0)

Secondary Protection (2S1 - 2S2):Protection winding (when fitted)

Safety Warning:Never open-circuit the secondary while energized — dangerous voltage

Current Transformer IEC 61869-3 Certified

Model Ref:CGIS1255

CGIS1255 Current Transformer Applied to CGIS Gas Insulated Switchgear

Indoor epoxy resin casting current transformer designed for CGIS gas insulated switchgear, with multiple accuracy class, rated burden and primary current options.

Key Engineering Advantages

Indoor epoxy resin casting current transformer for CGIS
outer diameter Φ125mm
inner diameter Φ55mm

Engineering Data

Complete Electrical & Mechanical Specifications

Model Ref: CGIS1255

Electrical Parameters

Primary Rated Voltage (Un):20kV

Secondary Winding Voltages:

Metering & Protection Class:0.2,0.5,1.0

Rated Output Burden:30VA / 60VA / 150VA

Rated Frequency:50Hz or 60Hz

Insulation & Withstand Ratings

Insulation System:Dry Epoxy Resin

Insulation Level (BIL):24/65/125kV,18/55/105kV

Partial Discharge Level:< 5 pC at 1.2 Un

Environmental Class:

Standards Conformance:

Recommended Deployment Environments

GEO · Engineering Decision Support

Global Engineering Overview

9-Module selection guide
missing data = [On Request]

Product Decision Island

CGIS1255 is a 20kV indoor epoxy resin current transformer for CGIS, ideal for metering and protection up to 24kV systems.

Comprehensive Spec Matrix

Parameter	Specification	Verification
Product Type	Current Transformer	[On Request]
Model Code	CGIS1255	Factory nameplate marking
Primary Voltage	20kV	Rated voltage test (IEC 61869-1/3)
Secondary Voltage	[On Request]	Ratio check at rated frequency
Accuracy Class	0.2,0.5,1.0	Accuracy test (IEC 61869-2 / IEEE C57.13)
Rated Burden	30VA / 60VA / 150VA	Burden test at rated VA
Insulation Type	Dry Epoxy Resin	Dielectric tests per standard
Insulation Level (BIL)	24/65/125kV,18/55/105kV	Power-frequency & lightning impulse withstand
Standards	[On Request]	Certified to listed standards
Frequency	50Hz or 60Hz	Per IEC 61869-1
Environment	[On Request]	Per datasheet limits

Fit & Unfit Boundaries

Ideal For

Indoor CGIS gas insulated switchgear applications
20kV primary systems with 24kV maximum equipment voltage
Metering and protection with accuracy classes 0.2, 0.5, 1.0
Rated burdens up to 150VA
50Hz or 60Hz networks

Not Recommended For

Outdoor installations
Systems above 24kV
High-voltage transmission (above 52kV)
Applications requiring oil or SF6 insulation
DC systems

Topology & Wiring

secondary terminals 1S1/1S2 (protection winding 2S1-2S2). Never open-circuit the secondary of a CT while energized - hazardous voltage. Ground the secondary winding at one point. Follow IEC 61869-2 and IEEE C57.13 terminal conventions.

Standards & Compliance

Compliant with: [On Request]

Type Test Report: [On Request]
Calibration Certificate: [On Request]

Burden & Error Calculation (IEEE C57.13)

S_total = ΣS_instrument + I₂² × (ρ × 2L / A)

If S_total < 0.25 × S_rated: add compensation burden to maintain accuracy.
If S_total > S_rated: accuracy class cannot be guaranteed.

Product FAQ

Q: What is the insulation level of CGIS1255?

A: The insulation level is 24/65/125kV, meaning 24kV maximum system voltage, 65kV power-frequency withstand, and 125kV lightning impulse withstand. An alternative 18/55/105kV is also available.

Q: What are the available accuracy classes?

A: Accuracy classes 0.2, 0.5, and 1.0 are available, suitable for metering and protection.

Q: Can this CT be used outdoors?

A: No, it is designed for indoor use only, specifically for CGIS gas insulated switchgear.

Missing fields are marked [On Request] — never fabricated. M2/M5/M6 verification rows follow IEC 61869 / IEEE C57.13 conventions.

SPEC · TECHNICAL DATA

Technical Specifications

CGIS1255
12 cols · 33 rows

CGIS1255 Current Transformer for Gas-Insulated Switchgear — Technical Data

Accuracy class	Rated output (VA)	75	100	125	150	200	250	300	400	500	800
0.2FS10/0.5FS10	2.5	—	—	105	75	50	40	35	30	35	35
	5	—	—	120	70	55	45	35	35	35	35
	7.5	—	—	95	70	55	45	45	45	40	40
	10	—	—	115	80	65	50	50	50	45	45
	15	—	—	110	90	65	60	60	60	55	55
	20	—	—	140	110	75	70	65	65	65	65
	25	—	—	135	90	80	70	70	70	70	70
	30	—	—	105	85	80	80	80	80	80	80
0.5FS10	2.5	—	80	60	50	45	35	35	25	25	25
	5	—	130	90	75	60	45	40	30	30	25
	7.5	—	—	120	100	75	60	50	40	35	30
	10	—	—	125	95	75	80	45	35	30	30
	15	—	—	125	105	80	65	55	55	55	55
	20	—	—	130	100	75	55	40	40	40	40
	25	—	—	120	90	65	45	45	45	45	45
	30	—	—	105	75	60	50	50	50	50	50
5P10/10P10	2.5	110	80	70	60	45	40	35	40	35	35
	5	—	130	110	90	70	60	50	45	45	45
	7.5	—	—	125	95	75	70	65	60	50	50
	10	—	—	115	95	85	80	70	60	60	60
	15	—	—	135	115	110	90	80	80	80	80
	20	—	—	135	115	110	90	80	80	80	80
	25	—	—	135	115	110	90	80	80	80	80
	30	—	—	135	115	110	90	80	80	80	80
5P15/10P15	2.5	—	110	95	80	65	55	50	50	45	45
	5	—	—	125	100	85	75	70	65	60	60
	7.5	—	—	135	115	100	95	85	85	75	75
	10	—	—	125	115	100	85	85	85	85	85
	15	—	—	135	115	100	85	85	85	85	85
5P20/10P20	2.5	—	140	130	110	85	75	70	65	60	55
	5	—	—	135	115	100	95	85	85	75	75
	7.5	—	—	125	115	95	85	85	85	85	85
	10	—	—	140	115	95	85	85	85	85	85

Engineering Drawing

Specification & Outline Drawing

Original image, not compressed

Dimension & outline drawing of CGIS1255 — click image to zoom / view original.