Exercise 3-4

LabVolt 3772-25 *Ire: file:. Voltage Transformer.

Transmission Grid “A”. The Transmission Grid 'A' consists of a transmission grid installed in a full-height EMS module. This module is used to open and close an ac power circuit under normal conditions or to interrupt this circuit under fault or abnormal situations. It can also be used for the connection of EMS motor/generator sets and loads as well as the protective relaying equipment for transmission grid protection.

Interconnection Modules. The Interconnection Module consists of three sets of twelve 4 mm safety banana jacks and three multiple-contact connectors mounted on the front panel. This provides an efficient means of interconnecting the electrical power system (EMS system) to the relays installed in the protective relaying control station..

Universal Fault Module. The Universal Fault Module consists of control relays, adjustable time delay relays, contactors, a solid-state relay (SSR), current limiting resistors, and an inductor, all installed in a full-height EMS module. These components allow faults to be inserted into the electrical power system (EMS system) for training in protective relaying applications.

Universal Fault Module.

Protective Relaying Station. The Protective Relaying Control Station has two sets of dc control relays, a dc power supply, and an interconnection panel are mounted on the rack. The two sets of dc control relays (six relays per set) allow basic contacts of protective relays (either normally open or normally closed contacts) to be converted into multiple normally open (NO) / normally closed (NC) contacts to actuate ac circuit breakers (contactors) in the electrical power system. Two of the dc control relays have adjustable time delay. The dc power supply is used to energize the relay coils. Also allows connection to the Interconnect modules,.

Protective Relaying Station. cifications Supply Input Wtage 20 V - Hz Input Current Output Voltage 20 v Output Current Control RAays Coil Voltage 20 V dc Comact Ratings Aat dc; 10 A at Relays 2 (CRI to CRA) Coil Voltage 20 v dc Cortact Ratings A at 150V dc; 10 A at 240V Control Relays 2 (TDi) Coil Voltage 20 V Comact Ratings SAat 120Vdc; Time Delay Range 1 to 10 s Control Relays 2 (TD2) Coil Voltage 20 V dc Contact Ratings 5Aat ac Time Delay Range to 60s panel Voltage Current Physical Charaderistks Dimensions (H x W x D) 546 711 rnrn (74.5 21.5 28.0 in) Net Weight 07.3 kg (236.11b).

Three-Phase Under/Over Voltage Relay. The Three-Phase Under/Over Voltage Relay is a protective relay that is sensitive to both undervoltage and overvoltage conditions in three-phase power systems. It trips when the voltage of any one of the three phases moves outside the set voltage limits. Voltage setpoint and hysteresis adjustments are provided for undervoltage and overvoltage. Two independent sets of contacts are provided: one for undervoltage and one for overvoltage..

Phase Balance/Sequence Relay. The Phase Balance/Sequence Relay is sensitive to phase unbalance, phase reversal, and phase loss in three-phase power systems. It can be used to initiate an action should any one of the hazards mentioned above occur. For instance, the sensitivity to phase unbalance allows protection of a three-phase induction motor against excessive temperature rise due to unbalanced supply voltages. Unbalance setpoint and time delay adjustments as well as two sets of contacts are provided. The adjustable time delay is a useful feature which can prevent premature relay operation on short duration supply fluctuations..

Four-Pole Squirrel-Cage Induction Motor. The Four-Pole Squirrel-Cage Induction Motor is a 0.2 kW squirrel-cage induction machine mounted in a full-size EMS module. The machine stator windings are independently connected (six jacks), allowing connection in either wye or delta configuration. Connections to the machine are made through color-coded safety banana jacks located on the front panel on the module. The front panel of the Four-Pole Squirrel-Cage Induction Motor module can be opened to install a Timing Belt on the pulley of the machine shaft. This permits mechanical coupling of this machine a dynamometer or prime mover. When driven by a prime mover, the Four-Pole Squirrel-Cage Induction Motor operates as a three-phase asynchronous generator..

Variable Three-Phase Power Supply (8821). It can be used to power most of the EMS modules of the Electricity and New Energy Training Equipment. This Power Supply provides dc power and ac power, both fixed and variable, single-phase and three-phase. Color-coded safety banana jacks provide access to all the power sources in the Power Supply. All these power sources can be used simultaneously, provided that the total current drawn does not exceed the maximum current rating. A built-in voltmeter with selector switch and liquid crystal display (LCD) indicates the voltage provided by any of the power sources. The input and outputs of the Power Supply are protected by independent circuit breakers..

Variable Three-Phase Power Supply. Specifications Param«er Requirements AC Power Network Installation AC Power Network Connector Maximum Current Outputs (•see note) Three- hase Fixed AC Three-Phase Variable AC Variable Fixed Low Power Included Access«ies Physical Characteristks Dimensions (H x W x D) Net Weight 3 phases (120/2(E V — 60 Hz). star (wye) configuration neutral and ground wires. protected by a 20 A circuit breaker NEMA L21-20 15 A 120/208V-15A-COHz M20J208V-5A-60Hz O- 120 V -8 A (three-phase halfwave rectified without filtering capacitor) 120 V — 2 A (three-phase half-wave rectified with 94gF capacitor) 24 V-3A.60Hz 3 m (10 ft) cord (1) Padm (1) 287 mm (12.1 x 11.3 19.5 in) The Power Supply cannot supply all the amounts of current indicat«i by the current ratings on its front panel at time. Current indicated for the fixed three-phase Output section can only be Obtaired if current is drawn from any Other section. t*cause this section is by the main circuit breaker comrnon to every section. If currents flow in other sections. the available current for the fixed ac three-phase output sectkyn decreases. The variable ac output *Ction and the variabk dc Output section are protected a set Of circuit breakers placed after the fixed ac thræphase Output section. which means that the current cap"ity has shared the two sections. For instance, if current of the variable dc output section is at of its.

AC Ammeter (8425). The AC Ammeter module is fitted with three separate multirange ac ammeters for simultaneous measurement of three-phase currents. Two of the three meters have identical ranges while the third instrument has one additional higher range for measurement of the starting current of single-phase motors. Meter ranges and scalar values of each instrument have been carefully selected for compatibility and are appropriate for the electrical values to be measured. All meter readings are direct indications and do not require the indicated value to be mentally multiplied by a constant. All meters are diode-protected against burnout..

AC Voltmeter (8426). The AC Voltmeter module is fitted with three separate multirange ac voltmeters for simultaneous measurement of three-phase voltages. Meter ranges and scalar values of each instrument have been carefully selected for compatibility and are appropriate for the electrical values to be measured. All meter readings are direct indications and do not require the indicated value to be mentally multiplied by a constant. All meters are diode-protected against burnout..