SPM LTDS Appendix 4 Fault Levels (Table 4) 132kV 1ph - copy

The tables provide details of the Peak Make and RMS Break duty. The three phase equipment rating (expressed in kA) refers to the RMS Break value. Switchgear ratings are also provided for each substation The fault level values provided in the appendix tables include a value for the assumed fault in-feed values from rotating apparatus associated with site load, in accordance with the guidelines contained in Engineering Recommendation G74.

Although the load associated fault currents are included in the values, as an indication of the G74 magnitude, the G74 Peak Make component value is displayed. While in some cases apparatus capability may be in excess of the design limit, as described in Section 2.4.3, system fault levels will always be constrained within the relevant design limit. The tables indicate those locations where the predicted fault level is equal to or greater than 95% of the plant capability.

All lower voltage interconnection between Primary substations has been assumed to run normally open. Short circuit currents at customer locations are based on the assumed system configuration detailed in Appendix 9: System Schematics (Table 9). Click here to access our full Long Term Development Statements for both SPD & SPM.

Note

A fully formatted copy of this appendix can be downloaded from the Attachments link below. To view this data please register and login. Definitions Name Description S/S Group The identifier for the substation group a substation is within.

S/S Name The identifier of the substation. Busbar Name Independent Parliamentary Standards Authority (IPSA) identifier for the faulted busbar. Voltage (kV) The operating voltage of the asset.

LV ('Low Voltage', generally 215V), HV ('High Voltage', >= 6.6kV and < 33kV), EHV ('Extra High Voltage', 33kV) or 132kV. System Impedance X (% on 100 MVA Base) System reactance, per unit on a 100MVA base. System Impedance R (% on 100 MVA Base) System resistance, per unit on a 100MVA base.

Existing System 1ph Peak Make (KA) The maximum possible instantaneous value of the prospective short circuit current and occurs at the first AC peak after fault inception. Due to the time elapsed; there is little decay of the DC component. Existing System 1ph RMS Break (KA) The RMS value of the AC component of the short circuit current at the time the circuit breaker is required to operate and takes no account of the DC component.

Switchgear Rating 1ph Make (kA) The short-circuit current that the breakers are capable of "making" i.e. closing onto an existing fault. Switchgear rating refers to capability of circuit breakers only. Substations are limited to the Fault Level Design Limits as outlined in Substation Fault Levels sections 2.4.3 of the LTDS main document.

Switchgear Rating 1ph Break (kA) The short-circuit current that the breakers are capable of breaking. It is expressed in kA RMS at contact separation. Switchgear rating refers to capability of circuit breakers only.

Substations are limited to the Fault Level Design Limits as outlined in Substation Fault Levels sections 2.4.3 of the LTDS main document.