Product Core Brief
- Model: DECS-100-B15
- Brand: DEIF (Danish Electronics Instrument & Factory)
- Series: DECS-100 digital excitation control system
- Core Function: Automatic voltage regulator — controls generator excitation current to maintain terminal voltage, manages reactive power (Mvar), and provides excitation protection functions.
- Product Type: Digital AVR / excitation controller
- Key Specs: Voltage regulation | Mvar / power factor control | Field current and voltage measurement | Protection and communication interfaces per configuration
- Condition: New Original / New Surplus (condition stated per line item on quotation)
Transparency note: The DECS-100-B15 designation identifies the hardware variant within the DECS-100 family. Regulation behavior is defined by firmware and the loaded parameter set, not by the part number alone. Confirm the nameplate and variant code of the unit being replaced.
Key Technical Specifications
| Category | Parameter | Value |
|---|---|---|
| Identification | Full Model | |
| Identification | Platform | DEIF DECS-100 digital excitation control system |
| Function | Module Type | Digital AVR / excitation controller |
| Function | Role in Topology | Owns excitation regulation; interfaces with CT/VT inputs, field circuit, and plant control |
| Compatibility | Replacement Rule | Part number, variant code, firmware, and parameter file must match the original |
| Mounting | Installation | Panel or relay-room enclosure mount |
| Communication | Interfaces | VT/CT inputs, field control output, serial/Ethernet per configuration |
| Maintenance | Hot Swap | Not supported — excitation must be taken to a safe state before removal |
| Electrical | Supply | Auxiliary control supply, per DECS-100 specification |
| Environment | Operating Condition | Relay room / control cabinet; temperature and ventilation limits apply |
| Failure Signature | Common Symptoms | Voltage drift, hunting, Mvar instability, loss of excitation protection |
| Supply | Lead Time | In-stock models ship within 48 hours |
Product Introduction
The DECS-100-B15 is a DEIF digital excitation control unit used on hydro and thermal generator sets. It regulates terminal voltage, controls reactive power output, and provides excitation-related protection.
For this part the replacement risk is parameters, not hardware. A controller that powers up and communicates can still be unsafe if the firmware revision or the loaded parameter set does not match the original — a mismatch can produce voltage hunting, Mvar instability, or a failure of excitation protection when it is needed. Verify the nameplate, the firmware version, and the parameter backup before ordering.
QA & Testing SOP
Identical for new original and surplus. No shortcuts.
- Inbound verification. Part number, variant code, revision, serial number, and firmware label photographed and matched against the customer’s DEIF documentation. Mismatched revisions are quarantined.
- Physical inspection. Connectors, pins, terminals, and board examined under magnification for rework, oxidation, or thermal discoloration.
- Bench power-up. Powered through a current-limited supply; startup sequence, status indicators, and self-diagnostics logged.
- Functional exercise. Secondary injection against the OEM parameter set; voltage sensing, control output response, and protection thresholds verified with a calibrated test set.
- Anti-static packaging. Moisture-barrier bag, desiccant, ESD label. Signed test record packed with the unit.
Installation Pitfalls & Guide
❗ Parameter set mismatch. A controller with a different firmware revision or an unloaded parameter file will power up and communicate, then hunt or regulate to the wrong setpoint. Load the validated parameters and confirm the revision.
❗ VT/CT wiring and polarity. Swapped, floating, or mis-grounded voltage sensing inputs are a more frequent cause of hunting than controller failure. Verify against the photographed terminal reference.
❗ Field circuit interface. Output range and field control signal type must match the installed exciter. A mismatch produces instability rather than an obvious fault.
❗ Auxiliary supply quality. Marginal or noisy control supply is a common source of repeated faults after replacement. Measure at the terminal, not at the supply output.
Replacement sequence:
- Pre-install — Confirm safe machine state, place excitation in a documented safe mode, apply lockout/tagout, photograph nameplate and terminal wiring.
- Removal — De-energize control supply and verify zero voltage, short CT secondaries as required, release retention, extract without stressing connectors.
- Install — Mount in the same position, torque terminals to OEM specification, reconnect against the photographed reference.
- Power-on test — Verify startup and communication, load firmware and parameters, confirm voltage sensing against a known reference, run a no-load voltage regulation check, then return to service.
Technical FAQ
Can I substitute a different DECS-100 variant if the exact one is unavailable? Only after engineering review. Variant codes differ in I/O capability and output rating, and a mismatch may power up yet regulate unsafely.
Is hot swap supported? No. Place the excitation system in a documented safe state before removal.
Why does the replacement controller hunt or drift after install? Most often it is not the controller. Check firmware revision, parameter load status, VT/CT polarity and grounding, field output settings, and auxiliary supply quality.
What warranty applies? New original units carry standard coverage as stated on the quotation. Surplus units carry a shorter, disclosed term confirmed before payment.
Is the DECS-100-B15 still supported by DEIF? The DECS-100 platform remains in DEIF’s portfolio, but individual variants move toward channel inventory over time. That makes revision, parameter, and lead-time confirmation more decisive than unit price on this part.
