In short. The standby diesel generator at TSGENCO’s Nizamsagar hydro power station was nearly 75 years old and still mechanically sound, but its control panel was not. Rather than replace a working engine and alternator, TSGENCO’s Nizamsagar R&M division ordered a new control panel for the 75 kW set from Reddy Generators in October 2019, through a competitive enquiry with three bidders. Reddy Generators supplied and installed the panel at the station, extending the life of the existing set for a fraction of the cost of a new generator.
| Customer | Telangana State Power Generation Corporation Ltd (TSGENCO), R&M Division, Nizamsagar |
|---|---|
| Site | Hydro Power Station, Nizamsagar, Kamareddy district, Telangana |
| Year | 2019 (purchase order dated 23 October 2019) |
| Scope | Supply and installation of a DG set control panel |
| Generator | 75 kW diesel generator set, nearly 75 years in service |
| Duty | Station standby (auxiliary supply for the power station) |
| Procurement | Public-sector competitive enquiry; three quotations evaluated, order placed after negotiation |
The requirement
A hydro power station needs its own standby supply. When the station is shut down or the grid is lost, auxiliary loads such as lighting, controls, battery charging and drainage must keep running, and the standby diesel set is what carries them. At Nizamsagar that duty fell to a 75 kW diesel set that had been in service for close to three-quarters of a century. The station needed it to start reliably and be controlled and protected safely again.
What we found
The engine and alternator of an old, slow-revving set built for continuous station duty can outlast several generations of controls. Here the weak point was the control panel: the wiring, switching and protection that start the set, show its condition and shut it down safely when something goes wrong.
The engineering decision: modernise, not replace
Replacing a 75 kW set means a new engine, alternator, foundation, exhaust and cabling, plus disposal of the old machine. If the engine still holds compression, the alternator insulation tests healthy and spares remain obtainable, a new control panel restores safe, dependable operation at a small fraction of that cost and disruption. This is the decision we recommend to many owners of older sets, and the reasoning is explained in generator replacement versus retrofit.
| Option | What it involves | When it makes sense |
|---|---|---|
| New control panel (chosen) | Replace controls, metering and protection; keep engine and alternator | Engine and alternator healthy; failures are in the controls |
| Engine or alternator overhaul | Rebuild the worn machine as well as, or instead of, the panel | Low compression, high oil consumption or failing insulation |
| Full replacement | New generating set, civil and electrical work | Machine beyond economic repair, or capacity or emission rules have changed |
Work performed
- Supply of a new control panel matched to the existing 75 kW diesel set
- Installation at the hydro power station
Outcome and limits
The station’s existing standby set was returned to service with a new control panel instead of being scrapped and replaced. A new panel does not renew the engine or alternator; their condition still governs the life of the set, and regular maintenance and load testing remain essential. See load bank testing.
Questions engineers ask about this project
Can a 75-year-old diesel generator still be worth keeping?
Yes, if the engine and alternator are healthy. Older station sets were built heavy and slow-running, and many outlive their controls. Test compression, oil analysis and alternator insulation first; if they pass, new controls are usually the most economical way to restore reliability.
What does a DG set control panel do?
It starts and stops the engine, displays voltage, current, frequency and engine readings, and shuts the set down on faults such as low oil pressure, high temperature or overspeed. A failed panel can make a sound generator unusable or unsafe.
Should a new panel be an AMF panel?
Only if the set must start and take load automatically on mains failure. Many station sets are started manually by operators; others benefit from automatic mains failure control. See AMF panels.
Engineering record reviewed by Srinivas Reddy, Managing Partner, Reddy Generators. Source: TSGENCO purchase order dated 23 October 2019. Last reviewed: 20 October 2026.
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