BS ISO 1540:2006

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements applicable to all systems
   4.1 General
   4.2 On-aircraft power sources
   4.3 External power sources
   4.4 Source/distribution system coordination
   4.5 Utilization equipment
5 Constant frequency (CF) a.c. power system characteristics
   5.1 General characteristics
   5.2 Steady-state characteristics
   5.3 Transient characteristics
6 Variable frequency (VF) a.c. power system characteristics
   6.1 General characteristics
   6.2 Consideration of CF power characteristics
   6.3 Steady-state characteristics
   6.4 Transient characteristics
7 D.C. power system characteristics
   7.1 General characteristics
   7.2 Steady-state characteristics
   7.3 Transient characteristics
8 Requirements allocation
9 Utilization equipment restrictions
   9.1 General
   9.2 A.C. power utilization
   9.3 Power factor
   9.4 Load switching transients
   9.5 Inrush current
   9.6 Input current modulation
   9.7 Input current distortion
   9.8 Maximum input capacitance
10 Power quality associated assumptions and background
   10.1 General
   10.2 Background to the document scope
   10.3 A.C. power system assumptions
   10.4 A.C. source equipment assumptions
   10.5 D.C. system assumptions
   10.6 D.C. engine starting power quality
   10.7 270 V d.c. input power

Specifies the characteristics of electrical power supplied to the terminals of electrical utilization equipment installed in an aircraft.

This International Standard specifies the characteristics of electrical power supplied to the terminals of electrical utilization equipment installed in an aircraft. It is intended to support the interface definition for user equipment designed to accept electrical power on a variety of new civil aircraft applications, such as those certified via the Technical Standard Order (TSO) certification process. It might not be desirable for equipment targeted to a single application or specific military application to follow this International Standard because of the penalties associated with multi-application.

This document also attempts to provide background to the development of these requirements that may be useful to those designing and/or integrating modern aircraft electrical systems. The delivered quality of this electrical power is a result of the combined characteristics of the electrical power source, distribution and user equipment. While only user equipment restrictions are specifically defined, background to key source and distribution equipment interfaces are identified in order to support development of the overall system.

A wide variety of electrical supply types and distribution parameters have been considered, as may be found on both small and large transport aircraft. Sources considered include physically rotating and static types, provided either on-aircraft, or as part of the ground support equipment. Distribution voltages addressed are

• nominal 14V, 28V and 42V d.c.;

• nominal 26V a.c., 400Hz, one-phase;

• nominal 115/200V rms and 230/400V rms a.c., both one-phase and three-phase, at either a nominal 400Hz constant frequency (CF), or over a variable frequency (VF) range which includes 400Hz.