IEEE 1158-1991 pdf free.IEEE Recommended Practice for Determination of Power Losses in High-Voltage Direct-Current (HVDC) ConverterStations.
IEEE 1158 When evaluating the economic coss of losses in a conventional ac substation, a distinction is made between noloadand load losses Thisapproach isdue to the fact that transformer losesare thedominating factor in ac substationsandthat transformer lossescan be broken down into two portions One part, which iscaused by magnetization, is presentwhenever the transformer is energized and is practically constant over the entire load range. lt is caled the noloadlosses The other portion isproportional to the load current squared and iscalled load losses.
On the other hand, there is no single piece of equipment that produces dominating losses in an HVDC converterstation. (See Table A.1 in Appendix A for a typical breakdown of station losses) The losses in an HVDC corverterstation are composed of the losses of various pieces of equipmernt, each of which has its own lass versus loadrelationship. For example valve losses are not proportional to the load curent squared (see Appendx B).Furthermore, when the station is energized, but in the standby mode descxibed below, the tbyristor valves will beblocked, and different loss mechanisms will apply from those that are found in normal operation A further variationin the losses comes about because some equipment may be cormnected only at certain load levels (For example, somefiltersand cooling towersmay be required only at higher loadings)Therefore, realistic valuesof the stationlosses canonly be obtained if the losses are calculated at several points between standby (no-load) and full load.
Whenevaluating the losses of HVDC converter stations it is recommended that two types of loses be distinguished;standby losses and total operating losses
These are the losses produced with the HVDC corverter station energized but with the valves blocked. Under thiscondition, the ac filtersand shunt compensating equipmert are not required, and they are not connected to the ac busSmoothing reactors and dc filters if any, are aso not energized However, the station service and cooling equipmentare cornected as required for immediate pickup of load.(Refer to Section 7.4.5 of lEEE Std 1030-1987 [10] forfurther explanation of the standby condition.) Standby losses canbeconsideredasbeing equivalent to “no-load” lossesin conventional ac substation practice.IEEE 1158 pdf download.