Special occasions Essay Example | Topics and Well Written Essays - 500 words

Special occasions - Essay Example For Muslims, there is a one-month of fasting being tediously observed during Ramadan to manifest the Prophet Muhammad’s historic acknowledgement of receiving the Quran from the angel Gabriel. These are special occasions that have been repeatedly and religiously observed for centuries. Further, there are special occasions that are deemed extraordinary only to the individual, the family and closest friends. One’s immersion to the world is celebrated annually through diverse means. Birthday celebrations for children are particularly a joyful occasion to cherish. Apart from the lavish preparations for food, party favors, mascots and invitations for guests, birthday celebrations are filled with loved ones and friends sharing precious moments and preserved through gifts, mementos and photographs that are kept to revere in the future. Another set of special occasions shared with family and friends are school affairs such as commencement exercises or graduations from one academic level to another, school prom, or being accepted in a prestigious university for higher education. What do all these occasions have in common that make them special? The most important element, of course, is me and the people who I share these events with. People tend to associate something special when activities are done out of the normal routine of daily endeavors. They only come once in a defined time period. The anticipation for the next event makes them extraordinary. Likewise, loved ones and friends exert quality time, money and effort to engage in intricate and elaborate preparations just to make one happy during these events. We acknowledge and realize that during these special occasions, we receive a blessing, a grace, a benefit, a lesson, a form of positive reward. During birthdays, aside from gifts, good food, and the company of loved ones, we get

Long-Term Sources of Finance Essay Example | Topics and Well Written Essays - 2000 words

Long-Term Sources of Finance - Essay Example preference equity, common equity, debt and leasing. Long-term Finances A business needs funds for capital investments such as fixed assets like plant, machinery, land, building, furniture etc. These assets must be financed with long-term financing sources. The chief financial officer (CFO) is usually responsible for making suggestions to the senior management and board of directors related to financing issues. These suggestions and recommendations carefully analyze the advantages and disadvantages of each long-term financing option. After the decision is made by the senior management and the board, the CFO is responsible for obtaining the long-term finances. The common forms of long-term finances are preferred stock, common stock, long-term debt and leasing. A firm faces need of different types of finances through its various stages of development. A firm in its start-up generally avail funds from the banks for personal loans, government agencies and personal savings. During the rapi d growth phase a firm uses internally generated funds or direct financing. The direct financing includes loans from insurance company, commercial banks or pension funds and financing by venture capitalists. The maturity phase is financed by issuing equity or debt in primary markets. The firm in its final stage finances from internal sources while making debt repayments or buying back the common stock (Weaver & Weston, 2004, p.311-312). Figure 1: Financing Sources Source: (Weaver & Weston, 2004, p.312) Sources of Long-term Finance Sources of long-term finance differ with the type and size of the firm. There are mainly two categories of financing-Equity and Debt. The equity financing consists of two types of equity instruments, one is preference stock and the second is common stock. The debt financing can take two forms, first long-term debt from financial institutions and second in the form of leasing. Each financing option is discussed as follows: Preferred Stock Preference capital is a distinctive type of long-term financing which combines the features of both debt and equity. As a hybrid security it has a fixed rate of dividend and ranks higher than the common equity in terms of claims over the firm’s earnings. The preference shareholders do not have voting rights as the common shareholders have. Advantages: The preference dividends can be omitted in case of low or zero earnings. This provides the firm greater flexibility and chance of surviving a downturn. However skipping a dividend may reflect dim view of the firm in investors’ community and may affect the share price as investors lose confidence and sell. Preference share capital is an additional source of capital which does not provide voting rights to the preference shareholders and therefore do not dilute the influence of ordinary shareholders. Fixed and limited preference dividends mean that the firms can retain or distribute common dividends in case of extra-ordinary earnings in a fisc al year. In case of limits on raising debts under the debt covenants, the preference share capital is a good alternative if a firm wants to expand raising external finance. Disadvantages: The high risk associated with capital and annual returns leads the preference shareholders to demand higher return than debt holders. The preference dividends are regarded as distribution of profits. Therefore they are not tax deductible. In comparison to this the lenders are not owners and so their interests are regarded as the expense

Literature Review Of Load Shedding Methods

Literature Review Of Load Shedding Methods In chapter 1, a brief discussion about active distribution networks was presented. The importance of operation of islanded distribution networks was discussed. This chapter is intended to give the reader a better understanding of the load shedding methods currently applied and proposed over the years. However, it is assumed that the reader is familiar with basic power system engineering. In section 2.2, the area of probability of islanding and the need for load shedding is discussed. To achieve this objective, existing load shedding methods are reviewed to understand their working principle, requirements, advantages and limitations. The main categories identified are the following (i) Manual / SCADA Load Shedding (ii) Load Shedding using thresholds, (iii) Adaptive Load Shedding, (iv) Intelligent Load Shedding and (v) Load Shedding Based on Static Optimisation which are described and discussed in sections 2.2 through 2.7 respectively. Finally a summary is given in section 2.8 from which a new load shedding method for an islanded distribution network able to address the limitations of existing methods will be proposed. probability of islanding There is by now a considerable amount of literature on load shedding. That most of the literature however deals with large interconnected systems. For smaller systems when a loss of mains / grid event occurs the islanded distribution network have different operating characteristics and restrictions that require different load shedding guidelines. These are due to the low inertia of the distributed generators, the limited spinning reserve and limited communication systems [0] [0]. Load shedding is a practice used power system and serves as a function to try to arrest any frequency or voltage drop when a fault isolating part of the distribution network occurs. Faults in power systems are inevitable, for various reasons such as adverse weather conditions, ageing and failure of equipment, accident, and animal contact. In general, faults happen when an abnormal physical contact occurs between lines or on lines to earth that create a short-circuit path. If the system is not well protected, the high fault current due to the short-circuit path can cause damage to the equipment in the system. Faults also affect the reliability and quality of the power supply, leading to power interruption by frequency and voltage collapse and voltage sag events. Regardless of the interruption period, the losses are often enormous both to the customers and power utility companies. There are two types of fault, determined by the physical nature of the short-circuit path: temporary or permanent. Common causes of temporary faults on overhead lines are lightning strike resulting in a flashover of the insulator; bird or animal contact; and momentary contact due to wind or trees. Faults caused by these events exist for a very short period of time. On the other hand, a permanent fault remains in the system until the short-circuit path is removed. Common causes of permanent faults in power system networks are cable insulation failure, objects falling on the overhead lines, dirt on insulators and lines falling to the ground. When faults occur, a protection device operates to isolate the faulty line from the rest of the system (loss of mains / grid). The generators designated to provide voltage and frequency control will respond to control the island voltage and frequency. In order to achieve smooth transition to island operation, the generators must firstly ride through the fault or failure and secondly act to balance the active and reactive power in the islanded network. With a carefully designed load shedding method the operation of the islanded distribution network might be possible. It is important however that the design of the load shedding method is designed on the understanding of the characteristics of the system involved, including system topology and dynamic characteristics of its generation and load. A poorly design method may be ineffective and eventually lead to total customer interruption. Over the years, however, utility experience and extensive studies on a number of systems have resulted in different methods guidelines. In the following section, principles and guidelines for load shedding methods are reviewed. manual / SCada Load Shedding Manual or operator initiated load shedding [0] is not a reliable method to be used to avoid frequency deviation. However it can be used by some utilities to manually shed load or open ties (interconnectors) with adjacent areas at a frequencies below automatic underfrequency thresholds. This type of action might be necessary to prevent any further frequency deviation and to recover the frequency back to the nominal value. This load shedding scheme cannot be used for the islanded distribution network as it will be very slow as the frequency and voltage in the network will collapse within few seconds making it impossible for the operator to decide the correct defence action required for safe operation. automatic Load Shedding using thresholds An automatic load shedding for transmission system using different schemes such as underfrequency, undervoltage and combinations of the two can be employed to avoid frequency or voltage collapse during a significant imbalance between generation and load. These types of load shedding methods are very dependant on off line studies of the systems dynamic performance and only consider the greatest probable imbalance between generation and load. These methods have to be coordinated with the protections of the generating units, shunt capacitors and other automatic actions that occur in the system during frequency and voltage variations. Underfrequency load Shedding The underfrequency load shedding scheme as explained in the following papers [0] [0] uses relays detecting the systems frequency. These are designed to operate on the instantaneous frequency value where they trip when the frequency drops below the set point of the relay. The shedding is accomplished in the systems distribution or transmission stations where major load feeders can be controlled by tripping of the circuit breakers (CB) automatically. Different settings can be applied in these load shedding schemes. Multiple stages can be used in the scheme [0]. The substation loads can prioritised and grouped according to the importance of the load. The relays can be set to control one or more groups of loads and when there is a frequency drop these can be disconnected sequentially where the group with the highest probability being disconnected the last. Each group disconnected should contribute to the system rate of change of frequency decline. If the load to be disconnected is small compared to the overall imbalance then the contribution will be insignificant and would cause further problems to the systems frequency decline. Another setting usual for this type of scheme is the time delay [0]. The time may can be required and used usually to avoid any frequency transient dips that could arise in the system. The time delay also avoids unnecessary load shedding by allowing the load / frequency controls in the system to respond to the frequency deviation. However load shedding performed with long time delays should be set appropriately as it will make the system more vulnerable to system stability if eventually load shedding is required. This method will work adequate in a situation where the system frequency decline is slow. For example, as discussed in [0], in the UK as stated in the NationalGrids GridCode each transmission area has to disconnect a defined percentage of the peak Demand that each Network Operator whose system is connected to the GB Transmission System shall disconnect by low frequency relays at a range of frequencies. The defined frequencies and the amount of loads are given in Table 1 -1. Table 1à ¢Ã¢â€š ¬Ã¢â‚¬Ëœ1: Load Shedding Scheme employed in the UK Frequency (Hz) % Demand disconnection for each Network Operator in Transmission Area NGET SPT SHETL 48.8 5 48.75 5 48.7 10 48.6 7.5 10 48.5 7.5 10 48.4 7.5 10 10 48.3 48.2 7.5 10 10 48.0 5 10 10 47.8 5 Total % Demand 60 40 40 The percentages in Table 1 -1 are cumulative such that, for example, should the frequency fall to 48.6 Hz in the NGET Transmission Area, 27.5% of the total Demand connected to the GB Transmission System in the NGET Transmission Area shall be disconnected by the action of low frequency relays. A significant drawback of this method is that the systems frequency must be already be low before the relay can operate which can delay the load shedding action and the frequency recovery of the system. Additionally these types of schemes usually shed more than the required amount of load. Undervoltage load Shedding Undrevoltage load shedding method has been successfully deployed in transmission systems to protect them from voltage collapse [0] [0]. System studies are required to determine which systems are potential candidates for suitable the undervoltage load shedding method. This method is most useful in slow decaying systems where the undervoltage load shedding relay time relays can coordinated accordingly and operate to alleviate the system from overload conditions and low voltages. Voltage collapse can be studied using steady state simulations for the identified areas using a power flow analysis. System planning engineers conduct numerous studies using P-V and Q-V as well as other analytical methods to determine the amount of load required to be shed to preserve voltage stability under different disturbances. Dynamic simulations can then determine the speed of the collapse and load shedding settings. An example as discussed in [0] in the US in the Puget Sound area, which is prone to voltage collapse has been studied. The voltage trip thresholds were determined from the results of steady state simulations of worst contingencies. The time delays for the relays were coordinated to address control actions of the automatic capacitor switching, generator limits, on load tap changing transformer using dynamic simulations. Table 1à ¢Ã¢â€š ¬Ã¢â‚¬Ëœ2: Load Shedding Scheme employed in the US Voltage (pu) Time delay (s) % Demand disconnection for Network Operator in Transmission Area 0.90 3.5 5 0.92 5.0 5 0.92 8.0 5 When the monitored bus voltages fall to 0.90 pu or lower for a minimum of 3.5 s then 5% of the load is disconnected. Additionally another 5% of load disconnection should occur when the voltage falls to 0.92 pu or lower for 5.0 s. There limitation associated with proper application of undervoltage load shedding is the location of its application.to where the relaying may be appropriately applied. If it is placed on a distribution line the effects of auto tap changers mask a system overload condition from the relay, or alternatively a line switching operation or the startup of a large industrial plant on one feeder could fool the relay. The relay would not be appropriate at locations directly adjacent to generation powerful enough to control bus voltages even during severe overloads. The relay is best applied to locations with fairly stiff voltages under all normal conditions, so a low voltage condition will reliably indicate a severe overload condition, as may be assumed to be the case at large substations associated with bulk power transmission lines and therefore this method cannot be effectively applied in islanded distribution networks where DG unit power and load demand varies. combination load Shedding In order to increase the security of the above discussed methods for underfrequency load shedding the relay could be set up to supervise the voltage, the current or the rate of change of frequency. According to their combined settings, the relay could either be blocked or initiate tripping of the CB to avoid any misoperations. One combination load shedding scheme is to use an underfrequency load shedding relay with voltage supervision. Basically the operation procedure of load shedding is blocked from operating unless the voltage is below a given threshold. The underfrequency relay will be able to trip the CB as long as the bus voltage it is monitoring is lower than a set point. Another combination is to use current supervision instead of the voltage. The purpose of the current supervision is to select which feeders to trip. This can achieved by monitoring which feeders are loaded above a certain point and then the relay will initiate the load shedding signal. An alternative is to use the rate of change of frequency for supervision [0] [0]. During a disturbance the supervision of the rate of change of frequency can block the tripping for very fast frequency changes but would allow for typical frequency decay rates. Also instead of measuring the instantaneous rate of change of frequency supervision is to use the frequency change trend. In other words by monitoring the average rate of frequency change will provide a more secure decision for tripping during disturbances. The load shedding decision of the scheme is made by monitoring the frequency change over a specified amount of time usually few hundred milli seconds. Therefore making the operation of the relay slower than the ones employing the rate of change of frequency. automatic ADAPTIve Load Shedding Adaptive control involves updating the amount of load to shed used by the method to cope with the fact that the conditions such as the power imbalance between generation and load of the system are time-varying or uncertain. It is important in these circumstances to minimise consumer disruption through proper design of the load shedding arrangements. An adaptive load shedding, is based on the relays reacting to a disturbance either by being instructed the amount to shed or by having certain defined criteria based on the rate of change of frequency. Anderson and Mirteydar in [0] present an adaptive methodology for setting of underfrequency relays that is based on the initial rate of change of frequency at the relay. The frequency performance of the islanded is represented by a linear system frequency response as shown in Figure 1 -1 and presented in more detail in the literature in [0]. Figure 1à ¢Ã¢â€š ¬Ã¢â‚¬Ëœ1: Simplified frequency response with disturbance input where: H = inertia constant (s) FH = fraction of total power generated by HP turbine TR = reheat time constant (s) Km = mechanical power gain factor R = droop characteristic (pu) D = damping factor Clearly the only observed quantity that gives any clue as to the size of the disturbance is the initial slope of frequency decline. The use of the initial slope to estimate the magnitude of the disturbance requires that every substation in the island will observe slightly different slopes and will therefore shed load based on different estimates of the disturbance. However on average the system as a whole will shed approximately the correct amount of load. To set the parameters for the relays as explained they are based on a simulation of the frequency response for the system. In the example given (H = 3.5 s, FH = 0.3, TR = 8.0 s, Km = 0.85, R = 0.06 and D = 1) the evaluation of the frequency and its slope against different amounts of disturbances are given in Table 1 -3. Table 1à ¢Ã¢â€š ¬Ã¢â‚¬Ëœ3: Initial Slope and Maximum Deviation vs Upset (frequency nominal 60 Hz) Pstep df/df ΆÃƒ Ã¢â‚¬ °max fmin pu pu/s Hz/s Hz Hz -0.2 -0.0286 -1.7143 -1.6438 58.356 -0.3648 -0.0521 -3.1260 -3.0000 57.000 -0.4 -0.0571 -3.4286 -3.2876 56.712 -0.6 -0.0857 -5.1429 -4.9313 55.069 -0.8 -0.1143 -6.8571 -6.5751 53.425 -1.0 -0.1429 -8.5714 -8.2189 51.781 The lowest frequency permitted in the system is 57 Hz from the nominal 60 Hz. Therefore when a magnitude greater than -0.0521 pu/s is observed load shedding must be triggered. This method relies on the fact that the amount of load shedding is a function of only the inertia constant and the observed slope. The inertia constant is the rotating kinetic energy of all units in the island divided by the total connected volt ampere rating of the units. This parameter has to be estimated. Therefore, the initial slope is the only unknown. The load shedding amount is computed in per unit, which makes it easy to apply to every load and to every load shedding relay. A positive is that communication is not required between relays and the boundaries of the island are not required to be known. However the drawbacks are that if it is applied for the islanding application of islanded networks this might not be possible as the method needs good estimates of the inertia of the system D, R, TR, Km and FH. This can significantly change with the varying DG units and loads in the distribution network. Another adaptive load shedding method presented by Terzija in [0] uses similarly as the previous method a variation of the typical swing equation. Due to the dynamic responses of turbines, governors, other control actions, spinning reserve, loads are not taken in account in the calculation of the required amount of load to be shed as given in . Where H is the inertia constants and assumed to be known in advance to the disturbance. The adaptive approach is based on real time estimation of fc (frequency of equivalent inertial centre) which is proposed to be calculated centrally by measuring the local frequencies at each generator. The proposed method assumes that the time constants in the power system are large and with modern communication this method would be possible for big power systems. However in distribution networks communication is believed not to change drastically in the near future making this application difficult to implement. This is because the estimation and control information are evaluated after the disturbance occurred. Van Cutsem and Otomega proposed a method in [0] which relies on a set of load shedding controllers distributed over the region susceptible to voltage instability. Each controller monitors the bus voltage and act on a set of loads located at that bus. Each controller acts when its monitored voltage falls below some threshold and trips at different time according the severity of the drop. The action can be repeated until the voltage is above the threshold voltage. The principle of operation of the controller is described as follows. The delay à Ã¢â‚¬Å¾ depends on the time evolution of V as follows. A block of load is shed at a time t0 + à Ã¢â‚¬Å¾ such that: where C is a constant to be adjusted. This control law yields an inverse-time characteristic: the deeper the voltage drops, the less time it takes to reach the value C and, hence, the faster the shedding. The larger C, the more time it takes for the integral to reach this value and hence, the slower the action. Furthermore, the delay is lower bounded: to prevent the controller from reacting on a nearby fault. Indeed, in normal situations time must be left for the protections to clear the fault and the voltage to recover to normal values. Similarly, the amount ΆPsh of power shed at time t0 + à Ã¢â‚¬Å¾ depends on the time evolution of V through where K is another constant to be adjusted, and ΆVav is the average voltage drop over the [t0, t0 + à Ã¢â‚¬Å¾]interval, i.e., Moreover, the whole system will tend to shed first where voltages drop the most. This location changes with the disturbance. Hence, the proposed scheme automatically adjusts the shedding location to the disturbance it faces. Note that the above features are achieved without resorting to a dedicated communication network. The controllers do not exchange information, but are rather informed of their respective actions through the power system itself. The drawback for this method for distribution network is that the tuning which consists of choosing the best values for Vth, C and K. A C and K combination suitable can be identified by minimising the total load shedding over all disturbance scenarios. Clearly this method would shed more loads for some scenarios. An additional concern is that the dynamic performance of the DG units and loads is not taken in account when performing load shedding if applied to the islanded distribution network and by trying to shed in steps the frequency drop in the network might drop significantly. automatic Intelligent Load Shedding Applications of intelligent load shedding in power system engineering (e.g. genetic algorithms, artificial neural networks, MonteCarlo etc.) have been demonstrated in [0] [0]. The characteristics which are inherent to intelligent methods, such as the ability to learn and generalization make it feasible for applications such as load shedding. You et al. in [0] discuss of a method that uses the rate of change of frequency to load shed. The method uses the same approach to calculate the required amount of load as in [0] and at the same time, the conventional load shedding method with undefrequency thresholds is incorporated to form a new two level load shedding method. The conventional load shedding method has longer time delays and lower frequency thresholds which can be used to prevent unnecessary load shedding in response to small disturbances. If the disturbance is large, the second layer will be activated and a block signal to the first layer is enabled. The second layer based on the rate of change of frequency load shedding will shed more load quickly at the early stage of the disturbance. Similarly as to paper [0], this method will have the same limitations when applied to the islanded distribution network. In the paper [0] which follows this study, the explanation of the selection of the settings for the relays is discussed. Agent technology is to try to assure that the method will withstand all possible disturbances. Traditionally after a major disturbance, the system is revisited and settings of devices and control actions are changed so that the system will withstand the same disturbance in the future. This however due to analysis of the system significant time and cost will be required. For the autonomous and adaptive learning capability for the agents, the reinforcement learning technique is used. Reinforcement learning is learning by interaction. The agent tries actions on its environment and then, the tendencies of taking particular actions are reinforced by receiving scalar evaluations of its actions. Thus determining the amount of load to be shed required to avoid collapse. The paper does not discuss whether the technique is applied online or offline through simulation. Clearly for the online this would not be ideal as it will take a lot of number of failures until the agents are properly set for that particular disturbance. For the offline simulation a concern is that for islanded distribution networks the topology, DG unit power and load demand will change thus making the decision of the action of the agents is difficult to train. Another concern is communication between agents. Fast communication would be required for coordinated decisions. Another approach to load shedding is the use of fuzzy expert system and is described in [0]. In this paper Sallam and Khafaga described a method to control the voltage instability by load shedding using fuzzy technique as fuzzy controller. The operation of the method relies on the experts knowledge which is expressed by language containing ambiguous or fuzzy description. The aim of this study is to design and analyse a fuzzy controller for the study to control against load and voltage instability by calculating the optimum load shedding as output. Similarly in [0] the authors propose genetic algorithms for the optimum selection of load shedding. These techniques search and optimise the amount of load shedding using objectives and constrains required for a practical load shedding method. Also in [0] the authors introduce another technique using the artificial neural networks is presented. To prepare the training data set for the artificial neural network, transient stability analysis of the power system is required and to find the minimum load shedding for various scenarios. By selecting the total power generation, total load demand and frequency decay rate as the input neurons for the method, the minimum of load shedding is determined to maintain the stability of the power system. In paper [0] Thalassinakis and Dialynas introduce a computational method using MonteCarlo simulation approach for the calculation of the settings of the underfrequency load shedding relays is discussed. The frequency performance as previously discussed in section 1.5 is used here as well. The strategy for the relay settings will be determined against amount of load to shed, time delay, rate of change of frequency and underfrequency level. A new strategy is developed by changing these settings. The MonteCarlo then computes the system through reliability indices of generating units, the system frequency and load shedding indices. load shedding based on static optimisation The first theory of applying load shedding using an on line dynamic simulation of the power system network was introduced by La Scala et al. [0]. Followed by an improvement of the method combing a control action to ensure angle and voltage stability enhancement in [0]. The first paper that introduced the same concept applied for large power systems to the smaller distribution network is described in [0] by Nelson and Aponte. A more recent study using similar technique is also presented in [0]. The paper presented in [0] describes the philosophy and the implementation of a preventive load shedding control algorithm for the application in dynamic security assessment. The methodology is based on nonlinear programming techniques, for assessing control actions to guarantee the dynamic security of power systems. The basic idea is that the online dynamic preventive control can be seen as a static optimisation problem with minimising function and equality and inequality constrains. The equality constrains consist in the discretisation at each time step of the differential algebraic set of equations representing the power system. The inequality constrains define a domain where the system trajectories should be contained in order to satisfy the requirements for the system performance stability and steady state voltage dips. In [0] the formulation includes corrective actions based on load shedding. The proposed method assumes that the analysis is performed to detect particular disturbances threatening the dynamic security of the system. The analysis is based suing the n-1 rule which is performed in advanced and applying the results immediately after the detected contingency. Each analysis has its associated strategies consisting with the corresponding amount of load to be shed at a fixed number of controlled nodes. The optimisation however is evaluated based on the steady state values of angle, voltage and active power (generator and load). Load shedding based on static optimisation performs load flow to calculate the initial P, V for all the nodes in the system. Then the method performs a transient simulation assessment to ensure the system is stable against angle and voltage. Followed by an approach to the minimisation of a function in presence of equality and inequality constrains consist in incorpora ting the inequalities in the cost function by adopting the penalty factor method and treating the whole problem as a minimisation in presence of the sole equality constrains by the use of Lagrange multipliers. This method has been used for synchronous generators in transmission systems. However in distribution networks because of the diversity of the generators and their ride through capability this approach could result in conditions where optimised solutions do not meet the requirements as shown in Figure 1 -2 [0]. Figure 1à ¢Ã¢â€š ¬Ã¢â‚¬Ëœ2: Ride through capability of Generating Unit, DC Converter or Power Park Modules. Explanation of graph required. Each Generating Unit, DC Converter or Power Park Module shall remain transiently stable and connected to the system without tripping. However for small generating units connected in the distribution network their transient behaviour could be as shown in Figure 1 -2 b and c where local protection and circuit breaker operation of generators or sensitive equipment will be disconnected after such a response. Similar to the voltage is for the frequency range. Therefore the load flow with corrective control for angle and voltage stability approach for the load shedding optimisation is not appropriate for distribution networks. In [0] and [0] describe of a method implemented in distribution networks where not only the amount of load shedding is optimised but also the time for the disconnection. The current trend is to apply the corrective measures as soon as possible or delayed for the sake of event discrimination. The study and results however show that when the corrective action is applied at the optimal time increased damping and enhanced response are observed. summary The use of load shedding as a tool to keep the network stable has been constantly evolving, and different approaches have been formulated. Relaying schemes like underfrequency and ROCOF [0] [0] are some examples of the mechanisms implemented to trigger a load shedding event. Typical load shedding schemes based on predefined threshold set points is quick, simple and reliable measure against system disturbance. When the frequency of the system reaches a specified threshold value, a time delay is inserted prior to the shedding action in order to avoid overshedding and assist the coordination of the next stage of load shedding action. This technique however when adopted for the islanded operation of small distribution networks would have several disadvantages. Too few frequency levels could lead to overshedding, but on the other hand, time delays between stages could add up and may not allow for enough load to be shed in time to re-establish nominal frequency. The implementation of ROCOF techniques mitigates some of these problems. The ROCOF value calculation is an immediate indicator of the power imbalance; but for the distribution network the variation of the DG units operation would make this measurement unreliable. Also the average ROCOF calculation may take too long and eventually make the load shedding method slow in operation. Even if accurate measure of the islanded distribution network ROCOF valu

Amerigo Vespucci :: essays research papers

Amerigo Vespucci Amerigo Vespucci, an Italian explorer was born in Florence, Italy in the year of 1454. Florence was a good city to grow up in for young Amerigo, because of the growing interest in the field of exploration. Some of the adults told young Amerigo about the wonders and riches of the Indies. Like the other Italian boys in his village, undoubtedly Amerigo was fascinated with by those tales.   Ã‚  Ã‚  Ã‚  Ã‚  Amerigo lived in the Ognissanti section of Florence with a lot of the Vespucci family. The Vespucci family was pretty well off, so Amerigo thought that he was in line for a lot of money after his father's passing, but his brother Antonio was highly favored over the rest of the children. Most of the Vespuccis living with Amerigo were merchants dealing in wine, olive oil, or wool. Not all of the Vespuccis were merchants, a small percentage of the Vespuccis were bankers. All of the family liked art and learning, poetry and music just like the rest of the Florentines. The ruler of these interesting Florentines was Lorenzo de' Medicior, who was also know as Lorenzo the Magnificant.   Ã‚  Ã‚  Ã‚  Ã‚  When Amerigo was older, but still a young man, his father Antastagio Vespucci sent him to the Monestary of San Marco to study with his uncle Giorgio. In his new school, Amerigo along with the other European boys learned Latin, math, grammar, history, Italian and Greek Literature, geography and astronomy. Amerigo learned to love astronomy, because he was fascinated about all of the shapes the stars made, that his uncle called constellations. Amerigo thought about traveling about the Earth, but he thought it to be impossible, because he was tought in school that the equator was a ring of fire that made the waters boil there.   Ã‚  Ã‚  Ã‚  Ã‚  Amerigo's hopes of traveling the world were become more realistic over time. The first thing that sparked this was the invention of the caravel, a light, narrow, 60 to 70 foot boat. The Portugese, that started making this boat had learned to rig the caravels to sail well against the winds and currents of the rough oceans. Another reality check occured when Amerigo was 19. What happend was the Portugese finally sailed to the equator and found no boiling seas, which proved the Roman theory that young Amerigo was taught in school wrong. But then came a period in his life that Amerigo realized he would never

Recommendation Report

MEMORANDUM DATE: 26 September 2011 TO: Muhammad Ali, CEO of Paintball Unlimited Pte Ltd FROM: Phoebe Soh, Supervisor for construction of new premise PROGRESS ON CONSTRUCTION OF INDOOR PAINTBALL ARENA AT LOT 25, JUSCO IPOH As requested, we are sending you the second monthly progress report on the developments of the construction of Paintball Unlimited 2. After overcoming some initial problems, we are making good progress on the construction of our new premise in Lot 25, Jusco Ipoh. Past ProgressDuring the past two months, we firstly finalized the estimated budget of our new project, the construction of Paintball Unlimited 2 at Lot 25, Jusco Ipoh. The estimated budget is at RM2. 0 – RM2. 5 million. We managed to secure the zoning approval to open up the premise. On confirming the location of the new premise, Lot 25 in Jusco Ipoh, which covers an area of 30,000 sq ft, we secured a two-year contract for the lease of the premise which will cost us RM240, 000 and will be paid in mon thly installments of RM10, 000.Next, we hired Flooring Pte Ltd to construct the flooring required for the different sections of our premise. Painters Pte Ltd was then hired to repaint the premise as the old paint coat was peeling. The lighting for our indoor arena was contracted to Lighting Pte Ltd. However there was a three-week delay in the installation of the wall lighting which led to a delay in the painting of certain sections of the walls. We also ordered 5 thousand T-shirts, caps and key chains each, designed by Nickly Pte Ltd. as a paintball keepsake. Current ProgressWe have started on the construction of the 4 sections of our arena which will be called ‘Desert Storm’, ‘Boggy Swamp’, ‘Jungle Safari’ and ‘Night Ops’. These names reflect the environment that customers will be playing in. It will be done up in such a way that it will simulate the actual conditions of the places mentioned. Desert Storm Progress on this section has been halted due to some unexpected delays. The design for this section includes obstacles such as statues of camels and 3 tons of sand for sand dunes, all of which we received before the due date.We are also constructing a mini swimming pool that will be done up to resemble an oasis. However, the delay was in the procuring of the artificial cacti. This is because the company we ordered the products from is currently facing a law suit to which the outcome is uncertain to us. Besides that, the blower we ordered from General Electric to create sandstorms is currently out of stock and the company was unable to confirm a delivery date. Therefore, further completion of this section is currently being put on hold and progress on the other 3 sections of the arena has begun. Boggy SwampProgress on this section of the arena is going smoothly. The fittings and the equipment such as the artificial mud, plastic mangrove trees and animals, plus other similar objects have arrived and are curre ntly being installed. We are also in talks with the manufacturer of those products to see if we can obtain its latest product which is a type of clay which releases an odour similar to that of a swamp to enhance the experience for future customers. However, we are not able to estimate the cost of the product and therefore do not know whether it will be within our budget. Jungle SafariProgress on this section of the arena has faced some difficulties. Some of the products that we have purchased for this section have been found to be defective. For example, the plastic trees that we have ordered been found to have large cracks in the structures and look very flimsy. Therefore, we have doubts on whether it will be able to withstand the impact of the shots from the paintball guns. We have brought up this issue to the manufacturer but have been unsuccessful in obtaining a response from them. Besides that, some of the construction workers have been absent for a few days, slowing down the c ompletion of this section.The contractor has projected a delay of up to two weeks due to this problem. However, he has been unable to provide a reason as to why his workers have not been turning up for work. Night Ops Progress on this section of the arena has encountered no problems thus far. The construction of the pillars and structures has been going according to plan and this section should be completed on time. However, there is a suggestion from the interior decorator to apply fluorescent paint on the obstacles and portions of the wall to make it more attractive and increase its appeal to potential customers.We feel it is a good suggestion and have contacted our appraiser to check if it is within our budget. Overall progress has been relatively smooth. The installation of air conditioners for the whole premise is going according to plan and is expected to be completed on time. The audio visual system that we are currently installing is also on schedule. However, there have bee n some unexpected increases in the prices of some of the equipment for the audio system, causing an increase in our overall cost and this will affect our estimated budget.Advertising of Our Project We are currently aggressively advertising the opening of the new paintball arena. Among the methods we are using are advertising through The Star newspaper. Our advertisement will start on December 3rd 2011 and will run daily for 6 weeks. We have contacted advertising experts from Advert Pte Ltd to design the advertisement for us and the design they showed us was more than satisfactory, thus we have chosen to use their sample. Besides that, we have assigned one of our employees to open up an official Facebook page for our project.It is currently being worked on and we have yet to see the final result. We have also contacted Dewan Bandaraya Ipoh to put up billboards for us at the Stadium roundabout and the Hospital roundabout for 6 months starting from December 1st 2011 to June 1st 2012. B esides that, we also contacted Voxel to put up an advertisement for us on their digital billboards to run concurrently with our others billboard advertisements. We feel that these locations are very strategic as a lot of people pass these areas. The design for the billboard is also under the same team that is designing our newspaper advertisement.However, they have yet to submit a design for us to review. Besides that, Jusco has agreed to include an announcement on the opening of our new arena in its monthly catalogue. Future Progress In the future, we plan to hire several employees to manage our completed arena. We have decided on †¢ Supervisor (1 person) †¢ Counter staff (2 persons) †¢ Instructors ( 4 persons) †¢ Referees ( 4 persons) †¢ First Aiders ( 2 persons) †¢ Cleaners (5 persons) As for the instructors and referees, we plan to send them for training should their knowledge on the subject of paintball be insufficient.We also plan to purchase the equipment needed for our arena. (Refer to appendix). The actual number of units will be decided on at a future date. Besides that, we are going to follow up on all the problems that have occurred in the construction of the site and make sure they are rectified. Once we are near completion, we will be able to provide an official launching date and send the company an estimate of our 1st year’s profit. We will also design a vision and mission statement for our arena based on the values of our company. Additional Information (breakdown of estimated budget) Expenses |Amount(RM) | |Furniture |250,000 | |Construction and Renovation |1,100, 000 | |Decoration |10,000 | |Weapons and Uniforms |60,000 | |Equipment |10,000 | |Business License, Permit and Insurance |100,000 | |Advertising and Promotion |170,000 | |Setup, Installation and Consulting fees |300,000 | |Total |2,000,000 | REFERENCE Paintball field owner. (2003). Retrieved October 29, 2011, fromhttp://www. stylecareer. com/pai ntballfield_owner. shtml Paintball guns net. (2009). Retrieved October 30, 2011, fromhttp://www. paintballguns. net/Paintball_Gun_Barrels/Paintball_Gun_Barrels/

Comparing the US Constitution to the 1918

In 1918, while the rest of Europe was still engaged in World War I, a newly formed communist government was developing in Russia. Much like 18th century Americans, they had just managed to overthrow what was viewed as a tyrannical government and hoped to form a new nation free of the injustices of the previous rule. Both countries wrote a new constitution as well as a declaration of rights to facilitate this, but their respective documents had vast differences. These disparities stemmed from differences in the ideologies of the new governments. The primary objectives of the Russian Declaration of Rights of the Working and Exploited People and the later constitution were the â€Å"abolition of all exploitation of man by man, complete elimination of the division of society into classes, merciless suppression of the exploiters, socialist organization of society, and victory of socialism in all countries. † Americans wanted equality of opportunity and personal freedom instead of the social equality desired by the Russians. The American constitution and Bill of Rights were created to protect personal liberties and individual freedom while the Russians were more concerned with the welfare and equality of the population as a whole. This difference is partially due to the differences in the conditions leading to revolution in each country. The American Revolution was initiated by the wealthy in response to what they considered unfair treatment by a foreign ruler while the Russian revolution was instigated by the poor in reaction to centuries of oppression and exploitation by the wealthy within their own country. In the years leading up to World War I, social unrest among the Russian people was spreading rapidly. There was a huge social gulf between the peasants who were former serfs and the landowners. The peasants regarded anyone who did not work as a parasite. They had always regarded as all land belonging to them. They regarded any land retained by the landowners at the time serfs were freed as stolen and only force could prevent them from taking it back. By the time Russia entered the war, one peasant rebellion had already been suppressed and several socialist revolutionary movements were developing. In February of 1917 a group of female factory workers and led a revolt in which the Tsar was dethroned, only to be replaced by a provisionary government composed of the Russian elite. When this government did not live up to its promises of an end to Russian involvement in World War I, the Bolsheviks (â€Å"majority†), a revolutionary movement led by Vladimir Lenin, overthrew the provisionary government in what bacame known as the October revolution. Upon seizing control, they immediately withdrew from the war and began constructing the world†s first ever communist government. One of the new government†s first acts was to write the Declaration of Rights of the Working and Exploited People. On July 10, 1918 the 5th Soviet Congress approved a constitution that, together with the Declaration of Rights, formed â€Å"the single fundamental law of the Russian Socialist Federative Soviet Republic†. Unlike the American Bill of Rights, the Declaration of Rights of the Working and Exploited People seems to have been meant to apply to all of mankind eventually, as is shown in Article 4: Expressing firm determination to wrest mankind from the clutches of finance capital and imperialism, which have in this most criminal of wars drenched the world in blood, the Third Congress of Soviets unreservedly endorses Soviet policy of denouncing the secret treaties, organizing most extensive fraternization with the workers and peasants of the combatant armies and achieving at all costs by revolutionary means a democratic peace for the working people, without annexations of indemnities, on the basis of free self-determination of nations. Their commitment to self-determination of nations was at least partially valid in that they gave Finland complete autonomy and withdrew their troops from Persia, but this may have resulted more from a lack of resources than altruism. Limited self-determination for the nations within the R. S. F. S. R. was also provided for in that the federal government was to be confined to â€Å"promulgating the fundamental principles of a federation of Soviet republics of Russia† while leaving the citizens of each region free to decide â€Å"whether they wish to participate in the federal government†¦ nd on what terms. † Several other liberties were provided for in the Russian constitution, many of which appear remarkably similar to freedoms provided for in the American Bill of Rights. Article 14 provided for freedom of expression, while Article 15 ensured â€Å"genuine freedom of assembly† and Article 13 guaranteed a separation of church and state as well as freedom of religious and anti-religious propaganda. All of these seem similar to the First Amendment of the U. S. onstitution, but they even went farther. Article 14 not only provided for freedom of press, but even promised every citizen access to â€Å"all the technical and material requisites for the publication of newspapers, pamphlets, books and all other printed material† as well as promising â€Å"their unhindered circulation throughout the country. † Article 15, besides guarantying freedom of assembly, promised to provide heated, lighted and furnished buildings for their gatherings. All things come at a price however, and all of these gifts from the government came at the price of true freedom of expression and assembly, as illustrated by Article 23: â€Å"Guided by the interests of the working class as a whole, the Russian Socialist Federative Soviet Republic deprives individuals and groups of rights which they utilize to the detriment of the socialist revolution. † In America, where distrust of the government is common, this passage would have been viewed as tyrannical and would not have been allowed in the constitution. The legislative powers of both the United States and Russia were given to a congress of elected officials. In the United States this is further divided into two houses of more or less equal power. In Russia, the All-Russia Congress of Soviets met only twice a year except in emergencies. During the rest of the year a smaller group called the All-Russia Executive Committee took on the responsibilities of the All-Russia Congress of Soviets. This group was chosen from the congress and remained accountable to it for all its actions. For decisions of major political importance they were required to check with the Congress before taking action. Unlike the United States congress however, both of the Russian bodies also had some degree of executive power, though most executive power was relegated to the Council of People†s Commissars. This council was created to exercise â€Å"general management of the affairs of the Russian Socialist Federative Soviet Republic. † This branch is given slightly more power than its American equivalent. In order to fulfill its responsibilities, the Council is given the freedom to take â€Å"what measures are necessary to ensure the proper course of life of the State. This may seem like limitless power, but they were also required to immediately notify the All-Russia Central Executive Committee of any orders or decisions it made. The Council of People†s Commissars was divided into 18 Commissariats: Foreign Affairs, Military Affairs, Maritime Affairs, Interior, Justice, Labor, Social Security, Public Education, Post and Telegraph, Nationalities Affairs, Finance, Transport, Agriculture, Trade and Industry, Food Supply, State Control, the Supreme Economic Council, and Public Health. Each division consisted of the Commissar and a small number of advisors. The All-Russia Executive Committee appointed the Commissars who then appoint advisors to their board. The appointments then had to be approved by the Executive Committee. In this way a system of checks and balances somewhat similar to the American system was put into effect.