DS200PTCTG1ABC | GE Mark V CT Termination Board

Description

Product Introduction

The DS200PTCTG1ABC is a precision current transformer termination board for GE’s Mark V DS200 series, used in Speedtronic turbine control systems. It provides conditioned, isolated CT inputs for generator protection, motor monitoring, and line current measurement.

The “ABC” suffix represents the highest-precision revision of the PTCTG family. Compared to the PTCTG1A, the ABC revision upgrades burden resistor tolerance from ±0.1% to ±0.05%, increases isolation to 2500 VAC, adds per-channel test points, and includes enhanced transient protection rated for 5 kV surge. This board is specified for applications requiring revenue-grade accuracy or compliance with IEEE C37.90 surge withstand.

Key Technical Specifications

Key Selling Points & Differentiators

• ±0.05% burden resistor accuracy – Revenue-grade precision. Each resistor is individually measured and certified. Typical boards use ±0.1% or worse. The ABC revision meets utility metering standards.
• Three-stage transient protection (5 kV surge rating) – MOV clamps large surges, gas discharge tube handles slow overvoltages, TVS provides final clamping to safe levels. Meets IEEE C37.90 for substation environments. Original PTCTG1A had only MOV protection (2 kV rating).
• Per-channel front test points – Banana jacks allow direct measurement of CT secondary current without disconnecting wires. Use a standard multimeter or portable calibrator. Saves hours during commissioning and troubleshooting.
• Dual-range operation per channel – Each of the 8 channels has an independent jumper for 5 A or 1 A selection. Mix ranges on the same board—channels 1–4 at 5 A for generator CTs, channels 5–8 at 1 A for auxiliary CTs.
• Non-inductive burden resistors – Wirewound with Ayrton-Perry winding. Inductance under 0.5 µH. No phase shift variation with frequency. Critical for power metering and protection relay coordination.
• Calibration certificate included – Each board ships with a NIST-traceable calibration certificate showing actual burden resistance, phase shift, and accuracy at 1 A, 2 A, 3 A, 4 A, 5 A per channel.
• 2-year warranty – Covers any failure including surge damage (within 5 kV rating), resistor drift, isolation breakdown, or test point damage.

Frequently Asked Questions (FAQ)

Q: What’s the difference between PTCTG1A, PTCTG1AB, and PTCTG1ABC?

The ABC revision is for revenue metering, protection relay calibration, or any application requiring traceable accuracy.

Q: Do I need external shorting blocks, or are they included?
A: Four shorting blocks are included. Each block handles two channels. They are rated for 20 A continuous and have a positive locking mechanism. Install them before disconnecting any CT wiring. We also include a safety placard that mounts next to the board with shorting procedure instructions.

Q: Can I use this board for generator differential protection (87G) requiring matched CTs?
A: Yes. The ±0.05% burden resistor tolerance and <0.2 degree phase shift make this board suitable for high-impedance differential schemes. However, you must use matched CTs on both ends of the generator winding. The board itself adds negligible mismatch. We recommend ordering a matched pair of PTCTG1ABC boards (serial numbers consecutive) for differential applications—contact us for this service.

Q: What is the test point output voltage?
A: The banana jacks are connected directly across the burden resistor. At 5 A input, you measure 0.5 VAC ±0.05%. At 1 A input (jumper selected), you measure 0.1 VAC ±0.05%. The test point does not isolate—it’s the same signal going to the analog input. Use a high-impedance meter (>1 MΩ) to avoid loading the burden resistor.

Q: The board has 2500 VAC isolation. Is that input-to-output or input-to-ground?
A: Both. Input terminals are isolated from output terminals (ribbon cable) at 2500 VAC. Input terminals are also isolated from the mounting plate (earth ground) at 2500 VAC. Output terminals are referenced to isolated ground (floating). This allows the board to float with the CT circuit, preventing ground loops.

Q: Can I use this board with 5,000:5 CTs on a 15 kV generator?
A: Yes. The isolation rating (2500 VAC) is sufficient for CT circuits on systems up to 15 kV phase-to-ground, assuming the CT secondary is referenced to ground through the burden resistor. However, the board itself does not provide primary-side isolation—that’s the CT’s job. For 15 kV and above, we recommend additional surge protection on the CT secondary leads. Contact us for application notes.

Q: What happens if I apply 600 A for 1 cycle (fault condition)?
A: The burden resistor is rated for 500 A for 1 cycle (16.7 ms at 60 Hz). At 600 A, the resistor may exceed its 500 A rating but typically survives. However, the transient protection may degrade. We test each board at 500 A for 1 cycle as part of QC. If you expect higher fault currents, install external current-limiting fuses on the CT secondary. We sell fuse kits rated for 20 A, 100 A, and 500 A thresholds.

Q: What QC tests are specific to the ABC revision?
A: Eleven tests, all documented with calibration data:

1. Visual: 20x magnification, especially burden resistor solder joints.
2. Burden resistance: Each channel measured at 0.1Ω ±0.0025Ω (0.05%). Four-wire Kelvin measurement.
3. Isolation: 3000 VAC for 5 seconds between input, output, and ground. Leakage <0.1 mA.
4. Surge test: 5 kV, 1.2/50 µs waveform, 10 positive and 10 negative pulses per channel. No output deviation >0.5% after test.
5. Accuracy sweep: 0.25 A, 0.5 A, 1 A, 2 A, 3 A, 4 A, 5 A, 6 A at 60 Hz. Error <0.1% across range.
6. Phase shift: Measured at 1 A, 3 A, 5 A, 60 Hz. Must be <0.2 degrees.
7. Temperature coefficient: Board placed in chamber at −40°C, +25°C, +70°C. Resistance drift <50 ppm/°C.
8. Overload: 30 A for 1 hour. Resistor drift <0.05%. 150 A for 1 second—no physical damage.
9. Shorting block test: 100 insertion/removal cycles. Contact resistance <1 mΩ in “SHORT” position.
10. Test point verification: Banana jack resistance to burden resistor measured <0.01Ω.
11. Calibration certificate generation: NIST-traceable values logged per channel.

Q: What shipping protection for this high-precision board?
A: Exceptional care. First: anti-static bag with humidity indicator. Second: ESD foam cradle with cutouts for the banana jacks and shorting blocks. Third: hard plastic clam shell case (custom molded). Fourth: double-wall box with “PRECISION INSTRUMENT” and “CALIBRATION INCLUDED” labels. Desiccant pack and shock indicator (if tipped or dropped, a red flag appears—inspect before accepting). Each board ships individually. Calibration certificate is laminated and attached to the outside of the clam shell case.

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