THE NEED FOR OFF GRID SERVICE COMPANIES IN ZAMBIA
IWill the pipeline be visible? N the case of a high head scheme as defined abo e where possible the pipeline will be buried and so out of site, but there may be times where the land is too tricky to work and then it will be routed on the surface.
All efforts should be made to ensure that it is not unsightly. Low head schemes may do this as well but because there is so little head of at least 1.5m but less than 5m, they need more water (sometimes the whole water course) to generate significant energy and the water cannot be easily accommodated through a penstock but through an open ume or inta e canal and may sometimes be installed directly in the river.
What is the turbine house like?
It can be anything from a small garden shed to a stone or brick built construction or it can be fitted into the corner of an existing building. This will be determined at the early stages of design.
What goes into the turbine house?
This is only applicable in high head schemes. Inside the turbine house you will find the turbine itself which you will find is ac- tually quite small in most cases), the electricity generator, a series of automatic or manual valves and the electronic load controller unit.
The turbine runner and generator type will be determined by site conditions. The two main categories of runners are impulse and reaction.
Impulse types squirt water through a nozzle that is directed at the turbine wheel-in decreasing order of head, they are Pelton, turgo and cross ow machines. Reaction runners are submerged in the ow of water and include Francis and propeller turbines. All low head tur- bines are reaction type.
What does the generator look like?
Basically it’s an electric motor, but instead of electricity powering it to do a job in the workshop or home, the waterpowered turbine wheel is driving it to produce electricity. Or it is an electric motor in reverse, in other words. In small hydro systems they are usually brushless permanent magnet.
What are the valves?
he valves control the ow of water to the turbine, ensuring that the pressure is maintained to drive it at the optimum speed for the amount of water avail- able. Generally there will be one or more spear valves, which are constantly variable nozzles controlling the amount of water in the jet that hits the turbine. In addition there may be one or more butter y valves which will be either Open or Closed and only function once the spear valve is at full capacity. Normally these will be automatically controlled. However, in low head schemes the water is channeled through a chute or canal intake to the turbine with no valves.
I’ve seen photos of turbine houses with electric heaters on the wall. Does the turbine house have to be kept at a constant temperature?
No, the heaters are used to ensure a controlled shut down of the system in the event of a power cut on the line which could be to a single house or a mini grid. They allow the energy still being produced to be safely ‘bled off’ protecting both the electrical appliances and your generator. Commonly these are known as ‘Dump loads”.
How do I get the electricity into my house?
Ensure that all the connections from the turbine to your property are correctly wired and covered with the appropriate safety devices such as main circuit breakers.
Is there an ongoing need for maintenance?
Most components do not require any ongoing/regular maintenance, apart from cleaning the mesh on the intake from time to time. Some parts of the system do benefit from annual chec s and there may be elements of the control systems which may require replacing after a few years. Small Hydro Solutions can draw up a maintenance plan and schedule to ensure the continued ‘health’ of your system. Further maintenance instructions are contained in a manual which comes together with the micro hydro generating unit. Maintenance instructions are contained in a manual which comes together with the micro hydro generating unit.
Ronald Lwamba has worked as a Town Engineer for the then Municipal Council of Livingstone and Zesco, initially as a Resident Engineer for Itezhitezhi rising to the post of Senior Manager, Civil Engineering where, among other things, he was in charge of the preparation of feasibility studies for hydropower projects. He holds a Bachelor of Engineering Degree (Civil) from the University of Zambia (1974), Post Graduate Diplomas in Water Resources Development (University of Roorkee, India) and Hydropower Development (University of Trondheim, Norway) and a Master of Engineering in Water Resources Development (University of Roorkee, India).