ERCOT System Operator Certification
UPDATED ACTUAL Exam Questions and
CORRECT Answers
There are electrical connections between ERCOT and the Eastern Interconnection. True or
False? - CORRECT ANSWER - True, there are two DC ties connecting ERCOT with the
Eastern Interconnection. There are no closed AC ties.
In December, 2009, ERCOT's electrical market was changed from a Zonal to Nodal model. This
means that: - CORRECT ANSWER - Transmission system congestion is now managed
between thousands of small points (nodes) in the ERCOT system, rather than between a few
large zones.
At a certain bus, current lags voltage by 72. What fraction of a cycle does this 72 phase lag
correspond to? - CORRECT ANSWER - 1/5th
What is the peak value of the voltage amplitude for a 345 KV AC voltage? - CORRECT
ANSWER - 345/.707= 244 KV
What is the phase difference between the two vectors in each of the following pairs?
(1) 345<90 and 345<60
(2) 138<-90 and 138<+90 - CORRECT ANSWER - (1) 30 , (2) 180
What is the per-unit value of a 345 KV bus voltage, if SCADA shows the actual bus voltage to
be 358.8 KV? If operating criteria require voltage to be within 5% of the nominal value, is the
bus voltage within limits? - CORRECT ANSWER - 1.04, Yes
What is the unit of measurement for electric current? For capacitance? For inductance? -
CORRECT ANSWER - Amps / Farad / Henry
UPDATED ACTUAL Exam Questions and
CORRECT Answers
There are electrical connections between ERCOT and the Eastern Interconnection. True or
False? - CORRECT ANSWER - True, there are two DC ties connecting ERCOT with the
Eastern Interconnection. There are no closed AC ties.
In December, 2009, ERCOT's electrical market was changed from a Zonal to Nodal model. This
means that: - CORRECT ANSWER - Transmission system congestion is now managed
between thousands of small points (nodes) in the ERCOT system, rather than between a few
large zones.
At a certain bus, current lags voltage by 72. What fraction of a cycle does this 72 phase lag
correspond to? - CORRECT ANSWER - 1/5th
What is the peak value of the voltage amplitude for a 345 KV AC voltage? - CORRECT
ANSWER - 345/.707= 244 KV
What is the phase difference between the two vectors in each of the following pairs?
(1) 345<90 and 345<60
(2) 138<-90 and 138<+90 - CORRECT ANSWER - (1) 30 , (2) 180
What is the per-unit value of a 345 KV bus voltage, if SCADA shows the actual bus voltage to
be 358.8 KV? If operating criteria require voltage to be within 5% of the nominal value, is the
bus voltage within limits? - CORRECT ANSWER - 1.04, Yes
What is the unit of measurement for electric current? For capacitance? For inductance? -
CORRECT ANSWER - Amps / Farad / Henry
