IS200EGDMH1ADE - Exciter Ground Detector Module

SPECIFICATIONS:

Part Number: IS200EGDMH1ADE
Manufacturer: General Electric
Series: EX2100
Product Type: Exciter Ground Detector Module
Number of channels: 12
Input span: 4-20 mA
Technology: Surface Mount
Common Mode Voltage Range: ±5 V
Maximum Lead Resistance: 15Ω
Analog output current: 0-20 mA
Operating temperature: -30 to 65 °C
Size: 8.26 cm high x 4.19 cm
Repair: 3-7 Day
Availability: In Stock
Country of Origin: United States
Manual: GEI-100467

FUNCTIONAL DESCRIPTION:

IS200EGDMH1ADE is an Exciter Ground Detector Module manufactured and designed by General Electric as part of the EX2100 Series used in GE Excitation Control Systems. The Ground Detection Module is used in the EX2100 Excitation Control System. It is a double slot, double height (6U) form factor board that mounts in the Exciter Power Backplane rack (EPBP). The field ground detector detects field leakage resistance between any point in the generator field circuit to ground, either on the ac or dc side. A simplex system will have one EGDM, and a redundant system will have three. The location of the EGDM(s) is shown in Figure 1. EXAM, the attenuator module, senses the voltage across the ground sense resistor and sends the signal to the EGDM(s) over a nine-conductor cable. The EXAM module is mounted in the High Voltage Module located in the Auxiliary Panel.

In a redundant control system, three EGDM boards are designated as Controller (C), Master 1 (M1), and Master 2 (M2), with their configuration determined by program pins on the P2 connector. The DSPX sends information on the active master through the EISB in the controller rack to EGDM C via a fiber-optic link. If M2 is the driver, C powers the relay in the Attenuator Module; otherwise, it remains unpowered for M1. Simultaneously, a differential signal is sent to M1 and M2, activating the signal generator on the selected master and determining the test command source for all modules. The active master then receives an Oscillator Signal from the DSPX via the fiber-optic link, converting it into a ±50-volt square wave. This signal is transmitted to the EXAM module and applied to one end of the Sense Resistor.

FUNCTIONS OF EXCITER GROUND DETECTOR MODULE :

• The signal conditioner receives an attenuated (10:1) differential signal from the Sense Resistor in the EXAM module. The signal conditioner is a simple unity gain differential amplifier with a high common-mode rejection ratio followed by an A-to-D converter (Voltage Controlled Oscillator VCO).

• The VCO feeds a fiber optic transmitter. The signal conditioner circuitry is powered by an isolated power supply to maintain personnel and equipment safety due to the high common-mode voltage at the Sense Resistor. The signal conditioner can measure the power amplifier output level by grounding the bridge side of the attenuated Sense Resistor on command from the control section.

• The C section of the controller receives all the programming and control signals from the various sources to determine which module will be the master. It also receives the oscillator signal from the DSPX so that it can generate a test command at each transition of the oscillator signal. The test command is a 250 ms long signal that can be retriggered on every transition of the oscillator signal (even if the period of the signal is less than 250 ms).

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FREQUENTLY ASKED QUESTIONS:

What is the function of the Exciter Ground Detector Module (EGDM)?

The EGDM plays a crucial role in monitoring and detecting ground faults within the excitation system. It continuously checks for insulation breakdowns, unintended ground connections, or leakage currents that could indicate potential failures. By promptly identifying these faults, the EGDM helps prevent damage to critical components, reduces the risk of system downtime, and ensures the stable and reliable operation of the excitation system.

How is the Oscillator Signal used in the system?

The Oscillator Signal is an essential component in the operation of the EGDM within a redundant control system. The active master receives this signal from the DSPX via a high-speed fiber-optic link, ensuring precise and reliable transmission. Once received, the signal is converted into a ±50-volt square wave, which serves as the test signal used to detect ground faults.

What type of communication is used between the EGDM and DSPX?

The EGDM and DSPX communicate using a high-speed fiber-optic link, which ensures reliable and noise-resistant data transmission. Fiber optics are chosen for their ability to maintain signal integrity over long distances while being immune to electromagnetic interference (EMI) and radio-frequency interference (RFI).