How do you determine whether a Bus in your power system requires a Reactor? How do generalize this method to check all the buses in your system?
Installing a bus reactor can help control over-voltage problems at transmission voltage substations. Often these over-voltage conditions will occur during a lightly-loaded system and return to normal at fully loaded times.
So to identify a bus that requires a reactor, step one might be to get a lightly loaded PSSE saved case.
Now we must identify those buses that are operating outside (higher than) their target voltage range. One option is to use the traditional VCHK. Which will tabulate the buses where voltage magnitude is outside a specified range.
psspy.vchk(sid=-1, vlo=0.9, vhi=1.1)
Unfortunately the results are just printed to the screen. We can do better. Lets get a Python list of the high voltage buses.
from psspy import abusint, abusreal
MAX_PU = 1.1
def transpose(subsystem_data):
ierr, values = subsystem_data
return zip(*values)
buses = transpose(abusint(sid=-1, string="NUMBER"))[0]
voltages = transpose(abusreal(sid=-1, string="PU"))[0]
high_voltage_buses = []
for bus, voltage in zip(buses, voltages):
if voltage > MAX_PU:
high_voltage_buses.append((bus, voltage))
# high_voltage_buses: [(3503, 1.14)]
(edit)
Hi again. I've asked around some of the engineers based in Melbourne, Australia. They mentioned that because the system jacobian is dependent on how the system is switched, that using it to determine sensitive entries could be difficult (also creating and using a jacobian is difficult in PSS/E - if anyone knows how please chime in).
Instead, they run multiple system studies for a large range of loading conditions and switching configurations to find cases where over voltage conditions occur.
Some of this is scripted with IDEV scripts, and to reduce the number of study cases, the engineer applies her knowledge of the power system to select the most likely candidates.
I still think looking at the jacobian would be instructive. If anyone can point me to any literature on this I would be appreciative too.
I like that transpose trick. It makes working with the PSSE data much easier.
Hi all! I would like know the probable reasons for high voltage in a system to build an algorithm for reactor placement. Jervis has already pointed out the case of light loading. What kind of switching conditions might lead to high voltage? Are there cases of over voltage at levels below 220KV?
@amaity maybe open a long line only in one end, fixed capacitors, very long lines
Comments
Great question, it would be much easier if we had access to the jacobian. I will have a think about this over the next few days.
@JervisW, how would the jacobian help?
@amaity My thinking was that the jacobian shows the voltage sensitivity to reactive power at all nodes in the system. You can determine where to place the reactor partly based on the most sensitive location.
@JervisW, that's a really good hint. I have been thinking over this too after asking that dumb question about the jacobian.