Abstract: At any point of time, a power system operating
condition should be stable, meeting various operational criteria and it
should also be secure in the event of any credible contingency. Present
day power systems are being operated closer to their stability limits
due to economic and environmental constraints. Maintaining a stable
and secure operation of a power system is therefore a very important
and challenging issue. Voltage instability has been given much
attention by power system researchers and planners in recent years,
and is being regarded as one of the major sources of power system
insecurity. Voltage instability phenomena are the ones in which the
receiving end voltage decreases well below its normal value and does
not come back even after setting restoring mechanisms such as VAR
compensators, or continues to oscillate for lack of damping against the
disturbances. Reactive power limit of power system is one of the major
causes of voltage instability. This paper investigates the effects of
coordinated series capacitors (SC) with static VAR compensators
(SVC) on steady-state voltage stability of a power system. Also, the
influence of the presence of series capacitor on static VAR
compensator controller parameters and ratings required to stabilize
load voltages at certain values are highlighted.
Abstract: Rice, which is the staple food in Sierra Leone, is
consumed on a daily basis. It is the most imperative food crop
extensively grown by farmers across all ecologies in the country.
Though much attention is now given to rice grain production through
the small holder commercialization programme (SHCP), however, no
attention has been given in investigating the limitations faced by rice
producers. This paper will contribute to attempts to overcome the
development challenges caused by food insecurity. The objective of
this paper is thus, to analysis the relationship between rice production
and the domestic retail price of rice. The study employed a log linear
model in which, the quantity of rice produced is the dependent
variable, quantity of rice imported, price of imported rice and price of
domestic rice as explanatory variables. Findings showed that, locally
produced rice is even more expensive than the imported rice per ton,
and almost all the inhabitants in the capital city which hosts about
65% of the entire population of the country favor imported rice, as it
is free from stones with other impurities. On the other hand, to
control price and simultaneously increase rice production, the
government should purchase the rice from the farmers and then sell to private retailers.