BS IEC/IEEE 61886‑1:2021 pdf download – Subsea equipment Part 1: Power connectors, penetrators and jumper assemblies with rated voltage from 3 kV (U max = 3,6 kV) to 30 kV (U max = 36 kV)
4.5 Design analysis The connector assemblies shall be subject to a design analysis on the critical areas of the design to verify that the design is capable of withstanding the stresses to which it may be subjected at all stages of its life. The design analysis shall as a minimum contain the following. • The connector assembly design shall be subject to a design failure mode effect and criticality analysis (DFMECA) and the results documented. The output from the analysis shall be used to identify areas of interest for further analysis, testing and quality controls. It may be necessary to augment the testing programme given in this document in order to evaluate features of the design that have been identified by the DFMECA. • Electrostatic, magnetic, thermal and mechanical finite element analysis, covering type tests and intended operational conditions shall be undertaken to evaluate the performance of the design where the performance cannot be inferred from other analysis. Consideration shall be given to worst-case design loads (e.g. test, storage, handling, installation/retrieval and operation) including fault scenarios (e.g. broken seal, short circuit) such that the design loads do not exceed electrical, thermal or mechanical limitations for any material. The analysis shall include the heat generated by the losses in the connector assembly itself. The analysis should also include possible nonlinear material properties. • Calculations to verify suitability of the pressure compensating system shall be undertaken. The analysis shall include test, storage, transportation, installation/retrieval and operational conditions. Any hysteresis (lag) in the performance of the compensation system shall be included. • The material properties and limitations used in the analysis shall be identified and documented based on qualified, recognised and repeatable fabrication processes. This is also applicable for bonding between materials. 4.6 Data sheet A data sheet shall be created for each connector assembly.
Rated current shall normally be specified for rated frequency in sea water at 20 °C for class I and in the relevant medium at the maximum ambient temperature as specified in Table 4 for classes II to IV. For connector assemblies operating in other conditions, the rated current and corresponding operational ambient conditions shall be clearly specified in the data sheet. If the extended temperature rise test is performed, the current carrying capacity versus ambient temperature characteristics shall be included in the datasheet. For systems involving harmonic currents, the system designer should select a current rating that considers the additional heat generated by the harmonic currents (both in the main conductor and cable screens as applicable). If considered required, and agreed between manufacturer and purchaser, additional temperature rise tests can be performed. 5.3.1 .3 Short circuit current rating Unless otherwise specified, the standard value of the rated thermal short-time current (I th ) shall be 25 times the rated current (I r ), t th being 1 s. Unless otherwise specified, the standard value of the rated dynamic current, I d , shall have amplitude of the first peak equal to 2,5 times I th . The maximum permissible short circuit temperature of the conductors shall be calculated in accordance with IEC 60986 and/or be verified by the FEA.
5.3.2 Earthing 5.3.2.1 Earthing of cable screens Connector assemblies shall have means for the earthing of housings and cable screens. The earthing connection shall be copper or a copper alloy, with a cross section area and current rating capacity similar to that of the cable screen; however, the cross-section area shall be a minimum of 6 mm 2 . For single phase jumpers (cables), screen currents could be considerable if the screens are earthed in both ends. If single-ended earthing of the screen is selected, the screen termination shall be designed to handle the induced voltage on the screen. 5.3.2.2 Shell continuity Unless specified differently in the project requirements specification or data sheet, connectors shall be designed to provide a shell continuity corresponding to 1 00 mV voltage drop or less at room temperature (20 °C) with a current of 1 0 A DC. 5.3.3 Dummy connectors Electrical voltage rating, including acceptable voltage test level, shall be clearly specified in the data sheet, and marked on each item.