The electrical variable-speed rack-and-pinion jacking … · The electrical variable-speed rack-and-pinion jacking system . ... • The automation scope consists PCS7 hardware / software,

© Siemens AG 2015. All rights reserved.

The electrical variable-speed rack-and-pinion jacking system Enhancing efficiency on jack-up rigs with an alternative to conventional hydraulic systems


Design (1)

Each jacking unit driven by electric motors to drive input / output planetary gearboxes and special designed 7 teeth pinions.

Jacking systems

Certification The jacking systems can be delivered with certificates from recognized Classification Societies such as ABS, DNV, Lloyds.


Design (2)

Pinion load is controlled by the system, not depending on special slip-motor

Reduced dimensions

Jacking system integrated into the jacking structure

Speed is reduced to zero before brakes are applied

Control system holds platform until all brakes are lifted

Reduced wear on the rack

Improved constructability and torsional stiffness

Reduce critical stress levels

Avoid brake wear

Avoid high pinion load,

Avoid brake slipping


Design (3)

• No overdesign

• High accuracy of load sharing over the pinions

• Less power and less cooling capacity required

• Integrated rack phase difference monitoring

• Redundancy, reliability, availability


Results

• High-speed jacking from 0.45 to 1.8 m/min

• Durable by optimized load sharing over the pinions = Less wear in gearbox / pinions

• Emergency operation possible when facing reduced power

• Accurate and integrated leg position indication and RPD safeguarding

• Redundant control system

• Use of standardized materials

• No need for special motors with high-slip requirements


Not only drilling rigs !


Major clients:

• CMHI • JURONG • DALIAN SIOC • SAMSUNG • LAMPRELL • DDW-

Paxocean

Scope Siemens includes delivery of gear boxes Siemens IND MD (formerly Flender)

• Seadrill • Statoil • Bestford

Capital • Noble Drilling • TS Drilling • COSL • Seajacks

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number Major clients: Major clients:


Scope of supply Siemens

• Siemens will engineer and deliver the electrical and control systems to drive the pinions that will lower and raise the platform.

• The automation scope consists PCS7 hardware / software, fully tested at our workshop in Zoetermeer. The drives & motors consist of standard materials with customer specific modifications and offshore ratings.


Technical characteristics

Separate safety layers:

• 1) over speed • 2) brake release • 3) motor control

Precise load sharing over the pinions = less wear and tear 0,0 m/min is a controlled state = pre-torque without manual intervention Multi layer safety= low power availability, jacking operation (up or down) continued. Rack Phase Difference monitoring (cm’s)


Differences (1)

Increased availability by “layer concept”. In case of limited power supply, jacking will still be possible by decreasing the jacking speed: There is a choice to operate the system with reduced performance when a complete layer fails


Differences (2)

Load

1 Chord

Speed

1 Chord

Load is always shared equally across the motors/pinions per leg. There are no step changes in the load or torque on the system. Smooth raising and lowering of the platform.


Differences (3)

• Operability: speed and precise control of the leg handling.

• Operator control via joysticks, pushbuttons and two touch screens (one man show).

• Status and set point interface is via a dedicated HMI located in the central control desk.

• Ultimate limit switches and over speed switches protect the system from inadvertent operational errors.

Ease of operation


Differences (4) : Enhanced safety

Each leg is equipped with an over-speed switch. This is a dominant safeguarding loop (SIL 2 design): if non-energized, an over speed switch generates a full stop in any mode of operation.

Safeguarding:

Drive control and control of brakes are done by the autonomous control system which means that the system won’t be able to release its brakes in case operations are not determined as being “healthy”.

We achieve this by means of: • the continuous measurement of input variables • the continuous control of output values

Continuous autonomous control functions:

© Siemens AG 2013. All rights reserved. © Siemens AG 2015. All rights reserved.

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The electrical variable-speed rack-and-pinion jacking … · The electrical variable-speed rack-and-pinion jacking system . ... • The automation scope consists PCS7 hardware / software,