A majority of drilling platforms and onshore drilling rigs are imported analog control system which were built before 2002. Conventional equipment suppliers include Ross Hill, IPS, Techpower, M&I, Siemens etc. However, some inherent problems exist in analog system such as difficult to calibrate the protection setting point, working point drifting, component aging and spare parts are difficult to find etc. Therefore, it is necessary to conduct upgrading and modification.
With the development of digital circuit and automation technology, digital power management system and control technique show a great advantage in drilling rigs. HICO undertook PMS upgrading and modification on COSL’s drilling platforms in 2005 and gained great achievements.
The characteristics are as follow:
1. The speed governing technology is developed in accordance with Siemens DC MASTER and has following functions: remote control, master/slave load balance, high speed, on-line diagnosis, over-speed protection, galloping protection, locked-rotor protection.
2. The Siemens PLC S7-300 is used as logic control unit, which can conduct communication via control bus and DC governing unit to realize start/stop sequence control, speed control, load distribution, safety interlock, event diagnosis function etc.
3. Color touch screen is used as logic control unit, which can provide the following functions: PMS status display, fault indication, alarm record, operation record, equipment running curve etc.. The maintainer can master all the system running condition via the touch screen, and to make rapid diagnosis for system fault.
4. The integrated computer work station has functions of display and diagnosis and record history running data. All running data can be referred by reviewing the history record. The integrated computer work station is extremely convenient to conduct fault diagnosis when equipment appears shutdown. The maintainer can monitor and diagnose the system fault via internet as it has access to the computer station.
5. Combined with SCR, PMS can limit the power via transferring the generator power to SCR. And regulate SCR load based on power station load so that it can prevent shutdown caused by sudden change of DC load system.
6. The DC top-driven control was brought into the control scope in order to prevent control differences among the control equipment which are supplied by different venders.
