IS200EGDMH1AFG GE EX2100 Ground Detection Module

Description:

The IS200EGDMH1AFG is a Ground Detection Module, crafted and engineered by General Electric for inclusion in the EX2100 Series, specifically tailored for GE Excitation Control Systems. This module plays a pivotal role within the EX2100 Excitation Control framework as a Field Ground Detector. It boasts a dual-slot, double-height (6U) form factor, designed to seamlessly integrate into the Exciter Power Backplane rack (EPBP).

Its primary function revolves around detecting field leakage resistance between any point in the generator's field circuit and ground, applicable to both AC and DC sides. In configurations, a singleton system employs one EGDM, while redundant setups necessitate three. The strategic positioning of these modules is illustrated in Figure 1. The EGDM operates alongside an Attenuator Module, which senses voltage across a ground sense resistor and transmits this data via a nine-conductor cable to the EGDM(s). Notably, the EXAM module, responsible for this sensing, resides within the High Voltage Module situated in the Auxiliary Panel.

In redundant control systems, the trio of EGDM boards assumes roles as Controller (C), Master 1 (M1), and Master 2 (M2). Their operational configurations are dictated by program pin settings on the P2 connector. Determination of which master drives the signal to the sense resistor within the Attenuator Module originates from the DSPX, traversing through the EISB in the controller rack to reach EGDM C. Upon receiving this instruction over the fiber-optic link, EGDM C activates or deactivates a relay in the Attenuator Module based on whether M2 or M1 is designated as the driving master. Concurrently, a differential signal is dispatched to M1 and M2, designating the active master. This signal triggers the signal generator on the selected master and sets the test command source on each module (M1, M2, C). Consequently, the activated master converts an Oscillator Signal received from the DSPX, via the EISB, into either a positive or negative 50-volt square wave. This converted signal is then routed via cable to the EXAM module, where it is applied to one terminal of the Sense Resistor.

A Signal Conditioner subsequently processes an attenuated (10:1) differential signal derived from the Sense Resistor in the EXAM module. Comprising a straightforward unity gain differential amplifier with high common-mode rejection, by an Analog-to-Digital converter (Voltage Controlled Oscillator, VCO), the conditioner feeds into a fiber optic transmitter. To ensure safety amidst high common-mode voltages at the Sense Resistor, its circuitry is powered by an isolated power supply. Moreover, the signal conditioner can measure the power amplifier's output by grounding the attenuated side of the Sense Resistor upon command from the control section.

Key Features Summarized:

- The controller's C section orchestrates programming and control signals from diverse sources to ascertain the master module. It also assimilates the oscillator signal from the DSPX to issue test commands at each oscillation cycle.
- These test commands, lasting 250 milliseconds, can be reinitiated on every oscillator cycle, provided the interval exceeds 250 ms.
- Each module's control section generates a non-retriggerable 250 ms test signal upon receiving the test command, necessitating intervals longer than 250 ms between successive tests.
- The power supply section transforms 24Vdc input from the EPSM through the EPBP into ±65Vdc (non-isolated) for the signal generator's power amplifier, and provides +5Vdc (isolated) along with ±15Vdc (isolated) for signal conditioning purposes.
- The power amplifier delivers a ±50 Volt square wave output with less than 1.0 Ohm impedance, limited to approximately 80 mA current. Under normal conditions, this operates every 5 seconds; during testing, this reduces to 400 ms cycles.

Datasheet Link:

IS200EGDMH1AFG GE EX2100 Ground Detection Module PDF Datasheet