power systems loss

TYPES OF CAPACITOR INSTALLATIONS What are the types of Capacitor Installation known? Capacitors are relatively easy to install and are among the most trouble-free electrical devices. Line capacitor installations are protected with conventional cut-out fused switches, and capacitor failure is rare if the appropriate fuse element is used. (Fuse rating should be closely coordinated with capacitor size.) There are several types of capacitors (see figure below). Following Load Reactive Power The most difficult aspect of capacitor application is the maintenance of proper balance between total kVAR of capacitors connected at any particular time and load kVAR present at that time. Like load kW, load kVAR changes over time, so some provision must be made to vary the total connected capacitive kVAR to roughly follow the load kVAR. Installing capacitors based on the peak load kVAR and leaving all these capacitors connected at off-peak times is strictly inadvisable, since excessive capaciti

CAPACITORS FOR POWER DISTRIBUTIONS SYSTEM How does Capacitors installed in the power distribution system affect the operation? The basic definition of a capacitor would be that it is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric (insulator). Capacitors are used as parts of electrical systems, for example, consist of metal foils separated by a layer of insulating film. When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them. Th

RUS BULLETIN 1724E-300 SUBSTATION VOLTAGE REGULATORS Voltage Regulators for Distribution System General Both three-phase and single-phase voltage regulators are used in distribution substations to regulate the loadside voltage. Substation regulators are one of the primary means, along with load-tap-changing power transformers, shunt capacitors, and distribution line regulators, for maintaining a proper level of voltage at a customer’s service entrance. A very important function of substation voltage regulation is to correct for supply voltage variation. With the proper use of the control settings and line drop compensation, regulators can correct for load variations as well. A properly applied and controlled voltage regulator not only keeps the voltage at a customer’s service entrance within approved limits but also minimizes the range of voltage swing between light and heavy load periods. The substation regulators may be located on individual feeders or in the transformer secondary

LINE VOLTAGE REGULATORS CHARACTERISTICS AND OPERATION Line voltage regulators' discussion and operation. Primary distribution feeders in rural areas often extend so many miles that maintaining proper voltage over the entire length of the feeder will supply poit regulators alone is impossible. Line regulators located approximately at the mid-point of such feeder provide additional regulation to support the voltage on the remote parts of the feeder. Characteristics of Line Regulators The most common types of line regulators operate similarly to substation regulators. However, line regulators are usually smaller, are more likely to be formed from single-phase units, and are physically constructed for platform mounting on a pole or poles. The discussion above of loss characteristics of substation regulators also applies to line regulators. The major operational difference is that line regulators normally are used only for boosting voltage, and there is no way to center t

How to minimize loss on Voltage Regulators Operation? To minimize losses on substation regulators , either separate units or substaton load tap changers, the high-voltage tap setting on the substation transformer should be set so the regulators will spend the maximum amount of time near the neutral position, since regulator losses increase as the regulator tap position farther away from neutral. Ideally substation regulators should spend approximately the same amount of time bucking voltage as they do boosting voltage. This keeps the regulators near neutral under average system conditions.

VOLTAGE REGULATORS IN DISTRIBUTION SYSTEM Voltage Regulators used in Power Distribution System? Voltage regulators affect the system efficiency in two ways. First, by maintaining proper voltage on the feeders they serve, regulators reduce losses on lines and distribution transformers supplied by the regulated voltage. Second, losses occur on the regulators themselves. Depending on regulator design, loading, and mode of operation, these losses can be quite high. Regulation at Substations Two major decisions are involved in the choice of regulating equipment to be installed in distribution substations. First, the distributor must decide whether to provide separate regulation for each outgoing distribution feeder or whether some of the feeders will share regulating equipment. For modest-sized substations with only one substation transformer bank and three to five feeders, the decision may come down to the choice between regulating equipment for each feeder and a single, large regulatin

SELECTION OF VOLTAGE REGULATING EQUIPMENT How do we select voltage regulators for installation in lines and substations? Distributors must consider many factors when deciding what regulating equipment to install in substations. These factors include: Equipment Maintenance Intervals, as related to the number of guaranteed tap-changer operations without maintenance. Capability of the equipment tocarry expected through-fault currents. Separate feeder regulators may be inadequate for the fault currents in some locations, whereas transformer LTCs are rated for the same fault duty as the transformer. Overall equipment purchase and installation costs. Space consumption in the substation yard. Whether or not separate regulating action is needed for each feeder, to include separate resistance and reactance settings for line-drop compensators and, Energy loss characteristics. Although energy loss is only one of these factors, a loss evaluation should be part of the engineering and econom