The project involved the design, supply, delivery, installation, testing and commissioning of Needle-Nozzle Assemblies and associated works for the Pelton Turbines at Nepal Electricity Authority's Ilam (Puwakhola) Hydro Power Station in Golakharka, Ilam. The scope covered two turbine units, with each unit incorporating two Needle-Nozzle Assembly sets, resulting in a total of four sets.

The works extended beyond equipment replacement and included site assessment, reverse engineering, 3D scanning, design and drawing submission, dismantling of the existing assemblies, installation of the newly manufactured systems, and integration with the existing Oil Pressure Unit and governing system. The project also required integration, reprogramming and final tuning of the existing ABB Symphony S+ SCADA system to accommodate the new Needle-Nozzle, Deflector, Brake Valve and associated operating mechanisms.

MSI undertook the project as an integrated electromechanical assignment covering equipment supply, hydraulic and electrical control integration, installation, testing and commissioning. Following implementation, the equipment was tested and confirmed by Nepal Electricity Authority to have met the performance criteria specified in the contract. Operational Acceptance / Taking-Over of the Needle-Nozzle Assemblies and associated systems became effective on 11 June 2026.

Objectives

The project was designed to achieve the following goals:

To reverse engineer, design and manufacture hydraulically operated Needle-Nozzle Assembly sets for two Pelton turbine units
To replace the existing Needle-Nozzle Assemblies and associated components with newly manufactured systems
To integrate the new assemblies with the existing Oil Pressure Unit and governing system
To provide new Deflector servomotors, Brake Jet Valves and electrically operated Cooling System Valves as specified
To integrate, reprogram and tune the ABB Symphony S+ SCADA system according to the new operating mechanisms
To complete installation, testing and commissioning of the new systems in accordance with the specified technical requirements
To provide mandatory spare parts, tools, maintenance devices and associated equipment required under the project scope

Key Deliverables

The following systems, instruments, and tools were supplied, installed, and commissioned as part of the project:

Needle-Nozzle and Deflector Systems

4 sets of hydraulically operated Needle-Nozzle Assemblies, comprising two sets for each of the two Pelton turbine units
Needle position feedback systems
Deflectors and Deflector Operation Mechanisms
2 sets of Hydraulic Servomotors for Deflectors with inbuilt LVDT, seamless pipe, flexible pipe, fittings and valves
Oil piping and fittings between servomotors and governor oil systems as required

Brake and Cooling Systems

2 sets of hydraulically operated 2-inch Brake Jet Valves
2 sets of electrically operated 4-inch Valves for the Cooling System
Hydraulic and electrical control system integration for the Brake Jet Valves and Cooling Valves

Engineering, Installation and System Integration

Site assessment, reverse engineering and 3D scanning
Design submission and final drawing submission
Dismantling of the existing Needle-Nozzle Assemblies, Deflectors, Deflector Servomotors and OPU, if applicable, with storage at the designated Puwakhola HPS location
Installation, testing and commissioning of the new Needle-Nozzle Assemblies with hydraulic and electrical control systems
Installation, testing and commissioning of the Hydraulic Servomotors for the Deflectors
Integration with the existing Oil Pressure Unit and governing system
Integration, reprogramming and final tuning of the ABB Symphony S+ SCADA system
Workshop assembly and testing
Corrosion protection following installation and testing

Spare Parts and Maintenance Support

2 sets of Needles with tips
2 sets of Seat/Nozzle Rings with Seat Ring Covers
1 set of LVDT for each type of Servomotor used
2 sets of Deflector tips/plates
2 sets of Bearings and Bushings for the operating mechanism
2 sets of Rings, Liners, Gaskets and Sealing materials for the Servomotors
2 Spring complete sets for Servomotors, if applicable
1 set of Hydraulic Control Valves and fittings, if applicable
1 set of Instruments and indicators, if applicable
1 set of Bolts, screws, nuts and washers, equivalent to 50% of those used
1 set of Braking Needle Valve with complete packing/sealing
Special tools and devices for assembly and maintenance

Challenges

The project involved several technical, execution, and coordination challenges associated with implementing a substation augmentation through an integrated project scope:

Developing replacement Needle-Nozzle Assemblies compatible with the existing turbine configuration required accurate assessment of the installed systems, supported by reverse engineering and 3D scanning
Dismantling the existing Needle-Nozzle Assemblies and associated mechanisms required coordinated execution before the new equipment could be installed
The new Needle-Nozzle, Deflector, Brake and Cooling systems had to interface with the existing Oil Pressure Unit and governing system
Mechanical, hydraulic, electrical and control components needed to operate as an integrated system rather than as independent equipment
The existing ABB Symphony S+ SCADA system required integration, reprogramming and final tuning to accommodate the operating mechanisms of the newly installed equipment
Installation had to be followed by systematic testing and commissioning to demonstrate compliance with the performance requirements specified in the contract

Solution

MSI adopted a structured execution and coordination approach to address the technical and implementation requirements of the project:

Site assessment, reverse engineering and 3D scanning were carried out to establish the technical basis for designing the replacement Needle-Nozzle Assemblies
The new Needle-Nozzle systems were designed and manufactured for the two Pelton turbine units, with associated Deflectors, operating mechanisms and position feedback systems incorporated into the solution
Existing Needle-Nozzle Assemblies and associated equipment were dismantled and transferred to the designated storage location before installation of the new systems
New Deflector Servomotors with inbuilt LVDT were integrated with the hydraulic and electrical control systems
Brake Jet Valves and Cooling System Valves were installed and integrated with their respective hydraulic and electrical controls
The new systems were interfaced with the existing Oil Pressure Unit and governing system to establish the required operational integration
The ABB Symphony S+ SCADA system was integrated, reprogrammed and tuned to accommodate the new Needle-Nozzle, Deflector, Brake Valve and associated operating mechanisms
Workshop testing, site testing and commissioning were incorporated into the execution process to verify the completed installation against the specified requirements

Impact

The completed project established a newly integrated Needle-Nozzle and associated control arrangement for the two Pelton turbine units at Puwakhola Hydro Power Station.

Provided four newly manufactured hydraulically operated Needle-Nozzle Assembly sets for the two Pelton turbine units
Integrated the new equipment with the existing Oil Pressure Unit and governing system
Integrated the new Needle-Nozzle, Deflector, Brake and associated operating mechanisms with the ABB Symphony S+ SCADA system
Provided dedicated Deflector Servomotors with spring return mechanisms and LVDT for faster Deflector closure during normal and emergency shutdown conditions, as specified in the project scope
Established supporting spare parts, tools and maintenance provisions for the installed systems
Completed testing of the equipment against the contractual performance criteria
Received Operational Acceptance / Taking-Over for the Needle-Nozzle Assemblies and associated systems effective from 11 June 2026

Conclusion

The Puwakhola Hydro Power Station project involved the replacement and integration of critical Needle-Nozzle, Deflector, hydraulic, electrical and control systems for two Pelton turbine units. The assignment combined reverse engineering, design, equipment supply, dismantling, installation, system integration, SCADA reprogramming, testing and commissioning within a single coordinated scope.

The project reflects MSI's capability to execute electromechanical modernization works involving both newly supplied equipment and existing hydropower infrastructure. The successful testing against contractual performance criteria and subsequent Operational Acceptance demonstrate completion of the integrated Needle-Nozzle Assemblies and associated systems in accordance with the specified project requirements.