A current transformer (CT) is an instrument transformer that scales high alternating current (AC) to a smaller, standardized level—typically 1 A or 5 A—for use in meters, relays, and protective devices. CTs offer both measurement isolation and minimal load to the primary circuit instru-measure.com+12Wikipedia+12YouTube+12Data Aqua Solutions+5GE Vernova+5GE Vernova+5instru-measure.com+3GE Vernova+3instru-measure.com+3. They are widely deployed in power generation, industrial distribution, and utility networks for precise current monitoring and protection Wikipedia.

? 2. GE Vernova & GE ITI: Brand & Manufacturing

GE ITI, part of GE Vernova’s Grid Solutions, manufactures a comprehensive range of CTs—from low-voltage (600 V) units to medium-voltage (5–35 kV) applications. Their main production facility in Clearwater, Florida produces over 500,000 dry-type instrument transformers annually GE Vernovaevents.vtools.ieee.org. Their offerings enable both revenue-grade metering and fault protection across industrial and utility applications Weschler Instruments+11GE Vernova+11flex-core.com+11.

? 3. Product Families & Model Highlights

✅ Low‑Voltage Window‑Type (Solid-Core)

• Model 114‑500: Single-phase, 50 : 5 A ratio, UL/CSA, IEEE C57.13 compliant, metering class 2.4 B0.1, relay C10, rating factor 2.0, window size up to ~4.62″ and insulation rated 600 V/10 kV BIL gibuys.com+7instru-measure.com+7instru-measure.com+7.

• Model 137‑122: 1200 : 5 A ratio, relay class C400, metering class 0.3 B1.8, rating factor 2.0, 5.50″ window, 50‑400 Hz, UL/CSA and IEEE‑compliant; suited for control panels, generators, and metering applications flex-core.com+2instru-measure.com+2instru-measure.com+2.

?️ Split‑Core (Take‑Apart)

• Model 600: 400–2000 A primary, 5 A secondary, metering classes B0.1–B0.5, 50–400 Hz, 0.6 kV insulation, 10 kV BIL; designed for retrofit in live systems without disconnecting bus or cables Weschler Instruments+1Weschler Instruments+1.

• Model 601: Larger window (4.5″ × 4.5″), same current range and specs, slightly higher burden capacities; ideal for retrofit situations where conductor clearance is an issue Weschler Instruments.

? Medium‑Voltage Indoor CTs

• CTW Series (5–35 kV Indoor CT): Vacuum-cast polyurethane resin cores, rated up to 35 kV, BIL up to 200 kV, UL recognized & CSA approved; designed for medium-voltage switchgear and utility systems GE Vernova+2GE Vernova+2Electro-Meters+2.

Also includes the JKM‑3C Series for 5‑800 A indoor low-voltage use, UL/CSA and IEEE C57.13 compliant, insulation up to 5 kV and 60 kV BIL

⚙️ 4. Key Specifications & Industry Standards

● Insulation & Frequency

• Standard insulation: 600 V, with a 10 kV full-wave BIL for low-voltage CTs; some MV indoor products rated for 35 kV or higher instru-measure.cominstru-measure.comGE Vernova.

• Frequency range: 50–400 Hz, allowing use in utility, industrial, and generator environments.

● Accuracy & Rating Classes

• Metering classes: up to 0.3 B1.8 (Model 137‑122), 2.4 B0.1 (Model 114‑500).

• Relay classes: C10, C400, depending on ratio and model.

• Rating factors: typically 1.5 to 2.0, allowing limited overload without accuracy collapse instru-measure.cominstru-measure.com.

● Burden, Knee-Point & Phase Shift

• Burden (VA or B‑class) determines maximum secondary load without accuracy loss.

• Knee‑point voltage applies to protection CTs exposed to fault current; it's the voltage at which CT ceases to track primary current linearly Wikipedia+1GE Vernova+1.

• Phase shift must be controlled for power and energy metering, especially under low power-factor loads Wikipedia.

?️ 5. Typical Applications

• Metering and Protection: High-accuracy models like 137‑122 service panelboards, generator circuits, and energy management systems.

• Retrofits and Maintenance: Split-core units (600/601 models) allow installation without interrupting live circuits.

• Utility & Switchgear Use: MV CTs such as the CTW series and JKM‑3C align with switchgear needs in substations and industrial switchyards.

? 6. Model Comparison Table

?️ 7. Selection Guide & Safety Best Practices

1. Identify the primary current range and conductor dimensions—ensure the window size fits.

2. Choose between split-core vs. solid-core: split-core for retrofit convenience; solid-core for measurement accuracy.

3. Pick the right current ratio (e.g. 1200 : 5 A or 50 : 5 A) based on meter or relay specs.

4. Select appropriate accuracy class: tighter ratio error needed for billing-grade metering; relay class based on fault duty.

5. Verify insulation and BIL ratings, especially in mixed-voltage environments.

6. Confirm burden rating and rating factor to maintain accuracy under normal and overload conditions.

7. Observe CT safety practices: never open-circuit secondary while primary energized; secure proper grounding and polarity.

? 8. Future Trends & Innovation

While GE ITI continues to produce high-quality electromagnetic CTs, emerging technologies are heading toward optical current transformers, which use optical, magnetostrictive, or thermal sensing for ultra-high precision, fast response, and enhanced safety. Adoption is expected in high-end applications in the coming years instru-measure.com

? Final Thoughts

GE ITI harnesses over a century of transformer heritage to deliver CTs that meet a wide spectrum of application scenarios—from basic metering to advanced protection across low‑ and medium‑voltage systems. Their model lineup—from split-core retrofit models (600 / 601) to solid-core precision types (114, 137) and MV CTs—offers engineers and utilities flexible, reliable instrumentation backed by UL, CSA, IEEE, and IEC compliance.

Need help choosing a model series, understanding data sheets, or defining specs for a project? Just let me know!