PCA Reference Data and Services
Toggle Dark/Light/Auto modeToggle Dark/Light/Auto modeToggle Dark/Light/Auto mode

Electrical calculations / analyses

A class with identifier http://rds.posccaesar.org/ontology/plm/rdl/PCA_100006174

MetadataThis section provides information about 'PCA_100006174' itself.

Source ontologynorsok-z001
NORSOK Z-001 rationaleElectrical calculations / analyses are required to be done according to IEC 61892-2 to confirm the design of the electrical system and corresponding ratings of the equipment:

General EMC planning shall be in accordance with IEC 60533, Annex B(Offshore) or IEC 61000-2-5 (onshore).

Arc flash study is required to be done according to IEEE Std 1584 to calculate arc incident energy.

NORSOK Z-001 extended definitionThe following studies are required to be done: - Electrical load study: - The electrical load study shall be done to determine major equipment ratings. - An allowance and contingency multiplication factor shall be applied to the estimated load to select the rating of generators and transformers. - Load flow calculations: - Load flow calculations shall be done to check the voltage profile and circuit loading under steady state conditions. Calculations shall include: - All general modes (such as main power mode, essential mode, emergency mode). - Different network configuration (such as open bus tie breaker, closed bus tie breaker with single incomer supply). - Different load scenarios (maximum load, no load). - Short circuit analysis calculations: - Short circuit calculations shall be done to determine maximum stresses during fault conditions. The results shall be used for specifying equipment ratings and to determine setting of protection. - Protection and discrimination study: - The protection and discrimination study shall be done to provide correct protection and discrimination. - The study shall include the following main subjects: - Network description. - Short overview of plant, with a subchapter per voltage level and system. - Operational modes description. - Full production mode, drilling mode, essential mode, emergency mode, UPS mode. - Protection relays and functions per circuit type. - Description of each individual protective device for the plant. - Fuse selection. - Fuse selection criteria, short circuit protection of consumer and contactor in starter/feeder, starting current versus starting time, load current and overload protection. - Protection principles. - Protection principles per system and operational mode. - This to include phase-phase faults and phase-earth faults in separate subsections. - Coordination of earth fault relays with different operating characteristic to be handled especially. - Protection principles per equipment type (equipment protection). - Protection relay templates. - Template per make/type of protection and per type of equipment to be protected. - Setting tables. - All individual setting parameters to be included. This shall also include protective relay settings on mechanical packages (e.g. firefighting system). - Current - time diagrams. - Logarithms current versus time curves (for visually documenting selectivity in the system and proper protection of equipment and cables). - All cases where curves indicate conflict with defined principles or criteria shall be explained. - Power system dynamic study: - The dynamic study shall be done to analyse the transient and dynamic performance of the power system. - Calculations shall include (as applicable) the dynamic performance when: - Starting/ energising largest motor/ consumer at each main switchboard. - Stopping/deenergising the largest possible group of consumers (due to e.g. process shut down). - Trip of one generator (or power source), with and without load shedding. - Short circuit in the primary distribution system, cleared by short circuit protection. - Other as required. - Calculations shall be done for different preconditions as follows: - All power modes (such as main power mode, essential mode, emergency mode, testing of the essential and emergency generator). - Different network configuration (especially those giving the extreme dynamic disturbance conditions). - Calculations of harmonic voltages: - Calculations shall be done to verify that harmonic distortions in all operating modes are within defined limitations. - Switching/equipment insulation study: - A switching/equipment insulation study shall when necessary be performed in order to specify the correct equipment insulation levels and to determine whether additional protections are required. - Electromagnetic compatibility (EMC):
 - The above referred standards as well as the manufacturer’s and supplier’s instructions with regards to EMC shall be followed and taken into account in the design.
  • Cable selection and sizing criteria:
    • An electrical cable sizing study shall be performed in order to establish cable sizing criteria.
    • The following subjects shall be taken into account when making general cable sizing criteria: - Consumer/ circuit nominal current. - Motor start current (motor circuits). - For voltage drop from generator terminals (in primary distribution system) or transformer secondary terminals (in secondary distribution system), stationary and transient. - Cables’ short circuits withstand capabilities (both mechanical and thermal). To be coordinated with short circuit protection. - Short circuit (phase to phase) at the end of the power cable supplying small power and lighting should cause instantaneous trip of the protective device. - The type of cable to be used for each purpose and area shall be fully described (e.g. mud/oil resistant, fire resistant etc.). - Current ratings for cables and de-rating factors for ambient temperature and cable grouping. - The study shall as a minimum summarise the following results: - Cable current capacity (maximum current) per type and size of cable.

Studies shall be done according to relevant IEC standards and more detailed company specific requirements.

If electrical power system design and simulation software is used, all modified or new files shall be transferred to Company as files of the software that is used. The report from the system study shall be delivered as a text file.

NORSOK Z-001 interests stakeholder categoryelectrical engineering
NORSOK Z-001 describes structural elementMain power (1.0 kV< u < 6.6 kV)
Emergency power (u = or >1.0 kV)
Main power (u =or >6.6 kV)
Main power (u = or <1.0 kV)
Emergency power (u<1.0 kV)
Battery and no-break
skos:broadMatchexplanatory technical information

ConstraintsThis section lists constraints that members of 'PCA_100006174' shall satisfy.

ContextThis section provides super- and subtypes as well as members of 'PCA_100006174'.