6TH MONTH FINAL Flashcards
THE LOSS OF THE MAGNETIC BONDS THAT BIND TOGETHER THE ELEMENTS OF A POWER SYSTEM IS KNOWN AS
ALL OF THE ABOVE
IF A 2 POLE GENERATOR’S ROTOR IS SPINNING AT 3601 RPM WHILE THE GENERATOR IS CONNECTED TO A 60HZ SYSTEM, HOW FAST IS THE GENERATOR’S TORQUE ANGLE CHANGING
6 DEGREES PER SECOND
NEGLECTING LOSSES, THE DIFFERENCE BETWEEN A GENERATOR’S MECHANICAL POWER INPUT AND ELECTRICAL POWER OUTPUT IS CALLED
ACCELERATING POWER
STEADY STATE INSTABILITY
SLOWLY DEVELOPING EVENT
TRANSIENT INSTABILITY
RAPIDLY DEVEILOPING EVENT
OSCILLATORY INSTABILITY
EXCITATION SYSTEMS ARE COMMON CAUSE
ACCORDING TO THE EQUAL AREA CRITERION FOR TRANSIENT STABILITY
THE DECELERATING AREA MUST AT LEAST MATCH THE ACCELERATING AREA
A GENERATOR IS ANGLE UNSTABLE WHENEVER IT’S TORQUE ANGLE EXCEEDS 90 DEGREES
FALSE
HIGH SPEED TRANSMISSION PROTECTION IS A BENEFIT TO ANGLE STABILITY BECAUSE
ALL OF THE ABOVE
THE PRIMARY DIFFERENCE BETWEEN AN OUT OF STEP EVENT AND A FAULT IS
THE SPEED AT WHICH THE IMPEDANCE CHANGES
WHEN A POWER SYSTEM IS ANGLE STABLE IT HAS WHAT 3 CHARACTERISTICS
SUSTAINED GENERATOR TORQUE ANGLES OF LESS THAN 90
SUSTAINED POWER ANGLES OF LESS THAN 90
A TORQUE ANGLE OF 25
WHAT ARE THE 3 CLASSIFICATIONS OF ANGLE STABILITY
STEADY STATE
OSCILLATORY
TRANSIENT
ANGLE STABILITY IS NOT LIKE VOLTAGE CONTROL IN WHICH A SYSTEM OPERATOR HAS THE TIME TO CORRECT VOLTAGE DEVIATION
TRUE
FOR A GENERATOR’S TORQUE ANGLE TO CHANGE THER EMUST BE WHAT
ACCELERATING POWER
WHAT ARE TWO ACTIONS AVAILABLE TO A SYSTEM OPERATOR TO ASSIST WITH MAINTAINING ANGLE STABILITY
MAINTAINING SYSTEM VOLTAGE LEVELS AS HIGH AS POSSIBLE
MAINTAINING THE SYSTEM IMPEDANCE AS LOW AS POSSIBLE
THE NOMINAL LOAD IS
EQUAL TO THE RATED LOAD
A PERIOD OF VOLTAGE INSTABILITY WILL ALWAYS RESULT IN A VOLTAGE COLLAPSE
FALSE
THE CRITICAL VOLTAGE AND CRITICAL MW TRANSFER ARE LOCATED AT THE
KNEE OF THE P-V CURVE
DURING VOLTAGE COLLAPSE PRONE CONDITIONS, TAP CHANGING TO SUPPORT SECONDARY VOLTAGE SHOULD GENERALLY NOT BE USED IF THE SECONDARY LOAD IS FORMED BY
NON-MOTOR TYPE LOAD
P-V CURVES INDICATE THE ___ MARGIN FROM VOLTAGE INSTABILITY WHILE V-Q CURVES INDICATE THE ___ MARGIN FROM VOLTAGE STABILITY
MW/MVAR
UVLS DIFFERS FROM UFLS IN THAT
UVLS IS BASED ON VOLTAGE WHILE UFLS IS BASED ON FREQUENCEY
IN WHICH TYPE OF VOLTAGE COLLAPSE DOES A KEY ELEMENT OUTAGE TRIGGER THE COLLAPSE
CLASSICAL VOLTAGE COLLAPSE
A P-V CURVE RELATES
THE MW TRANSFERRED ACROSS A SYSTEM TO THE VOLTAGE AT THE RECEIVING END OF THE SYSTEM
IN A RADIAL POWER SYSTEM, THE ADDITION OF SHUNT CAPACITORS AT THE RECEIVING END OF THE SYSTEM TENDS TO
FLATTEN THE P-V CURVE AND INCREASE THE CRITICAL VOLTAGE
IN WHICH TYPE OF VOLTAGE COLLAPSE DOES A SIMULTANEOUS STALLING OF LARGE AMOUNTS OF INDUCTION MOTOR LOAD TRIGGER THE VOLTAGE COLLAPSE
TRANSIENT VOLTAGE COLLAPSE
A RADIAL POWER SYSTEM IS A POWER SYSTEM IN WHICH GENERATION AND LOAD AREAS ARE SEPARATED BY A TRANSMISSION PATH
TRUE
TAP CHANGER IMPACT IS NOT ONLY DUE TO THEIR DRAW OF REACTIVE POWER FROM THE HIGH SIDE BUT ALSO TO
THEIR IMPACT ON THE MAGNITUDE OF CUSTOMER LOAD
POWER SYSTEM LOAD IS CONSTANTLY CHANGING
TRUE
THE INCREASING/DECLINING VOLTAGES DUE TO THE SUDDEN INCREASE IN MVAR DEMAND MAY CAUSE UNCONTROLLED TRIPPING AND RAPID COLLAPSE OF THE AREA POWER SYSTEM
DECLINING
DYNAMIC REACTIVE RESERVES ARE TYPICALLY CARRIED IN
SYNCHRONOUS GENERATORS, SYNCHRONOUS CONDENSERS OR SVC’C
IF MANUAL LOAD IS TO BE USED TO AVOID VOLTAGE COLLAPSE WHICH 3 OPERATING PROCEDURES SHOULD BE PERFORMED
PROVIDE ASSISTANCE TO THE SYSTEM OPERATOR TO HELP INDENTIFY VOLTAGE COLLAPSE PRONE CONDITIONS
DESCRIBE THE CONDITIONS IN WHICH LOADS ARE AVAILABLE FOR SHEDDING MAY BE USED
CLEARLY IDENTIFY WHICH LOADS ARE AVAILABLE FOR SHEDDING AND WHICH LOADS SHOULD BE SHED FOR DIFFERENT SYSTEM CONDITIONS
AS A SYSTEM OPERATOR YOU CAN PREVENT ALL TYPES OF VOLTAGE COLLAPSE
FALSE
AS A LAST RESORT TO AVOID A VOLTAGE COLLAPSE A SYSTEM OPERATOR SHOULD DO WHAT
MANUALLY DROP LOAD
