Comments on IEEE 57.21, Shunt Reactors Rated Over 500KVA

Section / Comment / Remark
3.1.1 / Letter “R” missing from title word Reactor
3.1.2 / Letter “S” missing from title word Shunt
3.1.2 / Word “(parallel)” to be added in the sentence … for connection in shunt (parallel) to an electric…
3.3.1 & 3.6.1 / Letter “D” missing from title word Dry
4.4.2 / Maximum allowed temperatures for cooling air for higher than 3300 feet need to be lowered.
4.6 / Figure 1 is missing.
4.6 / Most oil immersed shunt reactors are gapped core type and therefore exhibit very close to linear characteristics in the unsaturated portion of the curve.
5.1 / KVA rating of shunt reactor cannot be confirmed due to variation in actual impedance v/s designed
7.1 / Standard should define minimum % of rated voltage for reduced voltage testing. My proposal is 90%.
Table 4.A / Due to high force of attraction between core packets, Audible sound level test to be a routine test for shunt reactor rated 15MVAr 3 phase (or 5 MVAr 1 phase) or above
Table 4.A / Due to high force of attraction between core packets, Vibration test to be a routine test for shunt reactor rated 60MVAr 3 phase (or 10 MVAr 1 phase) or above.
7.2.3 / Sentence “For three phase shunt reactors, zero sequence……………….. measured as indicated” is to be deleted.
9.1.1 & Table 5 / Maximum system voltages to match with Table 4 and 5 of IEEE 57.12.00.
10.2.1 / Resistance measurement purposes: Purpose c and d of IEEE 57.12.90, Section 5 are to be added.
10.2.2.1 a) / Provide minimum time instead of a range ( 3 to 8 h). 3 hours minimum, in my opinion, is adequate for any size of SR.
10.2.5 c) / What is drop-of-potential method? Figure 2 is missing.
10.2.5 / Volt-Ammeter method to be added.
10.3 / Sections of dielectric tests are not in sequence of how the dielectric test done. IEEE 57.12.90 can be considered as good reference to re-assign section numbers.
10.3.3 / Over voltage test (Induced) with partial discharge measurement will require test transformer to be free of PD. Since shunt reactors are tested at with a source that can provide rated voltage of the shunt reactor itself, the test transformer itself has to be one voltage level higher than shunt reactor. For shunt reactors of345KV or above, it may be difficult to have test transformer of higher than 345KV class. Some consideration is to be given for such situation.
10.4.3.1 / More explanation/direction is needed as to when to use wattmeter, bridges etc.
10.4.3.1 / Figure 4, 5 and 6 are missing.
10.4.3.3 / In shunt reactor, no load loss, load loss, stray loss all are measured as load loss. Temperature co efficient of resistance is different for different materials involved in causing load loss. Therefore it is important to carry out load loss test very close to the reference temperature for accuracy sake. With that said, the actual temperature at measurement needs to be within +/-10 deg C of reference temperature.
10.5.7.2 / Since shunt reactors do not have different stages of cooling, I wonder why this section, of self-cooled, is needed.
10.5.8.1 & 2 / Unlike transformer, shunt reactor does not have situation of total loss run and rated current run. Hence these two sections are not required. Correction back to shut down is not applicable.