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How to determine the requirement of a bus reactor?

asked Mar 8 '12

amaity gravatar image

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?

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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 gravatar imageJervisW (Mar 9 '12)

@JervisW, how would the jacobian help?

amaity gravatar imageamaity (Mar 10 '12)

@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 gravatar imageJervisW (Mar 14 '12)

@JervisW, that's a really good hint. I have been thinking over this too after asking that dumb question about the jacobian.

amaity gravatar imageamaity (Mar 14 '12)

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answered Mar 15 '12

JervisW gravatar image

updated Jun 14 '12

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.

link

Comments

1

@JervisW, I am still working on this reactor problem. Could you please direct me to some literature/ article/ paper/ textbook that discusses the relationship between the jacobian and voltage sensitivity in detail.

amaity gravatar imageamaity (May 30 '12)

@amaity I've asked some of our colleagues and updated the answer with their reply.

JervisW gravatar imageJervisW (Jun 14 '12)

I like that transpose trick. It makes working with the PSSE data much easier.

chip gravatar imagechip (Jun 14 '12)

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 gravatar imageamaity (Aug 21 '12)

@amaity maybe open a long line only in one end, fixed capacitors, very long lines

waltterval gravatar imagewaltterval (Aug 21 '12)

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Asked: Mar 8 '12

Seen: 1,740 times

Last updated: Jun 14 '12