Volume 8 – Mechanical and Electrical Services - Malaysia Geoportal

Chapter 1 PUMPING INSTALLATION
A steep H-Q curve may be preferred for pumping water from the river where fluctuation of river
water level is prevalent, thus constant pump discharge is expected.
1.3 SYSTEM CHARACTERISTICS
Pump is normally designed with its best efficiency at the intersection of the pump head-discharge
curve and the system head curve. The system head curve can be represented graphically by
combining the static head and system friction head as shown below.
1.4 PUMPING ARRANGEMENTS
Fig. 1.5 Pump performance characteristic
It is a common practice to have a multiple-pumps pumping system to cater for the duty required.
Pumps may be arranged to operate independently with individual delivery system or to operate in
parallel in a single delivery pipeline. However, when operated in parallel, because of the additional
resistance incurred it is unlikely to achieve the theoretical increase in flow rate. Where large
quantities of discharge are required at high heads, multiple pumps in series may be used. However,
such system is rarely common in DID application.
1.5 PUMP AUTOMATIC CONTROL
Hitherto, most of the pumping stations are provided with automatic control system with manual
override. A control based on water level in the pump sump or in the discharge canal is commonly
used as a control constant for irrigation and drainage applications. The automatic level-responsive
pump control is designed for (a) pump-up mode in filling up the canal to the designed full supply
level for irrigation purpose or (b) pump-down mode in keeping the sump water level under a certain
level for flood control.
For reliable automatic control, especially in land drainage pumping station, due consideration shall be
given to the consequences of the failure of any station components in the design stage. All practical
provisions should be made for continual station operation under such component failure conditions.
Critical components may be provided in duplicate as standby and additional pumping unit shall be
provided. For larger pumping stations, standby generating-set may be provided as an alternative
source of power supply in the event of power outage.
1-8 March 2009