1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2017 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)Tel: +1 724-776-4970
4、 (outside USA)Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/AS1831A AEROSPACESTANDARDAS1831 REV. A Issued 1987-06 Revised 1997-10 Reaffirmed 2017-10 Supersed
5、ing AS1831 Electrical Power, 270 V DC, Aircraft, Characteristics and Utilization of RATIONALE AS1831A has been reaffirmed to comply with the SAE Five-Year Review policy. TABLE OF CONTENTS1. SCOPE . 31.1 Purpose . 32. REFERENCES . 32.1 SAE Publications 33. DEFINITIONS . 34. GENERAL REQUIREMENTS . 64.
6、1 Aircraft Electric Power System 64.1.1 270 V DC Power . 64.1.2 Power Source Impedance . 64.2 Distribution System . 64.3 Utilization Equipment 64.4 Equipment Polarity 65. DETAILED REQUIREMENTS - AIRCRAFT ELECTRICAL POWER SYSTEM 65.1 270 V DC Power System Characteristics . 65.1.1 Steady-State Voltage
7、 65.1.2 Ripple 65.1.3 Transient Voltage 95.1.4 Emergency Power . 95.1.5 Engine Start 9TABLE OF CONTENTS (Continued)6. LOAD DEMAND CONSTRAINTS . 96.1 User Equipment Constraints . 96.1.1 EMC Limits 96.1.2 DC Ripple Current Demand 106.1.3 User Input Current Inrush/Initialization 106.1.4 User Load Deman
8、d and Rate . 106.1.5 User Equipment DC Ground Isolation . 106.1.6 User Equipment AC Ground Isolation . 106.1.7 User Equipment Input/Output Isolation . 106.1.8 Protection of User Equipment . 106.2 Other Electrical System Operation 116.3 Power Requirements Data 117. GROUND SUPPORT EQUIPMENT CHARACTERI
9、STICS 117.1 270 V DC Electric DC Power System Description 117.1.1 Type of Power . 117.1.2 Voltage Sensing 127.2 Power System Characteristics 12FIGURE 1 270 V DC System Transient Voltage Limits . 7FIGURE 2 Frequency Characteristics of Ripple in 270 V DC Electric Systems 8SAE INTERNATIONAL AS1831A Pag
10、e 2 of 12_ 1. SCOPE:This SAE Aerospace Standard (AS) establishes the characteristics and utilization of 270 V DC electric power at the utilization equipment interface and the constraints of the utilization equipment based on practical experience. These characteristics shall be applicable for both ai
11、rborne and ground support power systems. This document also defines the related distribution and installation considerations. Utilization equipment designed for a specific application may not deviate from these requirements without the approval of the procuring activity.1.1 Purpose :The purpose of t
12、his document is to assure compatibility between aircraft electric systems or ground electric systems and airborne utilization equipment. See ARP4729 for recommended practices.2. REFERENCES:The following publications form a part of this document to the extent specified herein. The latest issue of SAE
13、 publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however,
14、 supersedes applicable laws and regulations unless a specific exemption has been obtained.2.1 SAE Publications :Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.ARP4729 Document for 270 Voltage Direct Current (270 V DC) System3. DEFINITIONS:3.1 AC CURRENT DEMAND : The AC current
15、 demand is the non-DC component of current drawn by a load.3.2 ABNORMAL OPERATION: Abnormal operation occurs when a malfunction or failure in the electric system has taken place and the protection devices of the system are operating to remove the malfunction or failure from the remainder of the syst
16、em before the limits for abnormal operation are exceeded. The power source may operate in a degraded mode for a defined duration where the power characteristics supplied to the utilization equipment exceed normal operation limits but remain within the limits for abnormal operation, before the protec
17、tion devices are triggered.SAE INTERNATIONAL AS1831A Page 3 of 12_ 3.3 DISTORTION FACTOR : The distortion factor is the ratio of the voltage distortion to steady-state DC voltage.3.4 DISTORTION SPECTRUM: The distortion spectrum quantifies DC distortion in terms of the amplitude of each frequency com
18、po-nent.3.5 DISTRIBUTION SYSTEM : The part of the electrical system used for conveying energy from the point of regulation of the 270 V DC source to the utilization equipment.3.6 EMC (ELECTROMAGNETIC COMPATIBILITY) : EMC is the capability of electronic equipment or systems to be operated in the inte
19、nded operational electromagnetic environment at designed levels of performance while maintaining an acceptable level of emissions and maintaining an acceptable level of susceptibility.3.7 INTERRUPTION SENSITIVE LOADS : Loads that cannot maintain normal operations during power interruptions longer th
20、an 50 s.3.8 NORMAL ELECTRIC SYSTEM OPERATION: Operation of the primary electrical system including all the functional electric system operations required for vehicle operation and mission support in the absence of an electric system failure. These operations occur at any given instant and any number
21、 of times during flight preparation, take-off, airborne conditions, landing, and anchoring. They include all system functions required by all phases of aircraft operation, except during the electric starting of the propulsion engine, when required.3.9 OVERVOLTAGE AND UNDERVOLTAGES: Overvoltage and u
22、ndervoltage are those voltages which exceed the normal limits.3.10 POINT OF REGULATION (POR) : That point in the system where voltage is sensed and referenced for voltage regulation, usually the source side of the 270 V DC bus power contactor.SAE INTERNATIONAL AS1831A Page 4 of 12_ 3.11 RIPPLE: Ripp
23、le is the repetitive variation of voltage above and below the steady-state DC voltage during steady-state electric system operation. Sources of ripple may include, but are not limited to, voltage regulation, stability of the DC power source, commutation/rectification within the DC power source, and
24、load variations within utilization equipment.3.12 RIPPLE AMPLITUDE : Ripple amplitude is the maximum absolute value of the difference between the steady-state and the instantaneous DC voltage.3.13 SPIKE: A variation from the controlled steady-state level of a characteristic which occurs for an extre
25、mely short duration measured with a peak-sensitive measurement instrument.3.14 Steady-State DC Voltage : The steady-state DC voltage is the average of the instantaneous DC voltage over a period of 1 s.3.15 TRANSIENT: A short term changing condition of a characteristic beyond the steady-state limits,
26、 returning to the steady-state limits within the specified time period.3.16 TOTAL HARMONIC DISTORTION : The root-sum-square of all the AC RMS Volts at individual harmonic frequencies measured in(RMS AC Volts)/(Steady-state DC Volts) * 100.3.17 VOLTAGE DISTORTION : The RMS value, measured at a discre
27、te frequency, of the alternating voltage on the steady-state DC voltage level.3.18 270 V DC POWER SYSTEM: That group of connected generation, distribution, controlling, protection, and conversion equipment active in supplying 270 V DC electric power to utilization equipment.SAE INTERNATIONAL AS1831A
28、 Page 5 of 12_ 4. GENERAL REQUIREMENTS:4.1 Aircraft Electric Power System:An aircraft 270 V DC electric power system consists basically of a main power source, emergency power source, power conversion equipment, control and protection devices, and an interconnection network (wires, cables, connector
29、s, etc.).4.1.1 270 V DC POWER:The 270 V DC power system shall be a 2-wire or negative ground return system having characteristics defined in 5.1.4.1.2 Power Source Impedance :The output impedance of the electrical power system source shall be characterized in the generating equipment specification a
30、t the source terminals.4.2 Distribution System :The distribution system shall be designed to furnish power at the utilization terminals in accordance with Figure 1.4.3 Utilization Equipment :Utilization equipment shall maintain specified performance when using power with characteristics which are sp
31、ecified in Section 5. Performance changes caused by ground support power shall be identified.4.4 Equipment Polarity :Equipment sensitive to polarity reversal shall provide its own protection by physical or electronic means.5. DETAILED REQUIREMENTS-AIRCRAFT ELECTRICAL POWER SYSTEM:5.1 270 V DC Power
32、System Characteristics :Characteristics of 270 V DC aircraft power at the input terminals of utilization equipment shall be within the limits specified in this section and in Section 6. The characteristics of electric power at the utilization equipment terminals shall conform to the requirements spe
33、cified herein, and shall be so installed and protected that the failure of any power source and its disconnection from the system will not result in subsequent impaired performance of the remaining power sources.5.1.1 Steady-State Voltage :The steady-state voltage shall be within the limits specifie
34、d in Figure 1.5.1.2 Ripple :The ripple voltage under normal operating conditions shall be within the limits as specified in Figure 2.SAE INTERNATIONAL AS1831A Page 6 of 12_ FIGURE 1 - 270 V DC System Transient Voltage LimitsSAE INTERNATIONAL AS1831A Page 7 of 12_ FIGURE 2 - Frequency Characteristics
35、 of Ripple in 270 V DC Electric SystemsSAE INTERNATIONAL AS1831A Page 8 of 12_ 5.1.2.1 Voltage Distortion:The frequency domain spectrum of the ripple voltage under normal operating conditions shall be within the limits of Figure 2 at the input terminals of the utilization equipment. These limits app
36、ly with all utilization equipment installed and operating. Distortion induced by individual utilization equipment should be below the limits shown on Figure 2 by a margin defined in the equipment specification when operating from a source impedance representative of its installation on the aircraft.
37、5.1.2.2 Total Harmonic Distortion :Total harmonic distortion shall not exceed 3%.5.1.3 Transient Voltage :Transient voltage shall be within the limits of Figure 1 for all operations of the aircraft electric system.5.1.3.1 Normal Electrical System Operation :For normal system operations, the DC volta
38、ge shall be within the limits of Figure 1. Under conditions of normal bus transfer, switching and paralleling, interruption of the DC supply shall not exceed 50 ms (50 s for interruption-sensitive loads). During the transfer, the DC voltage transient shall be within the limits of Figure 1 except tha
39、t the lower normal limit in Figure 1 shall not apply during the source transfer interval.5.1.3.2 Abnormal Electrical System Operation : For abnormal system operations, the DC voltage shall be within the abnormal limits of Figure 1.5.1.4 Emergency Power : Emergency power characteristics shall meet th
40、e same requirements as primary power characteristics.5.1.5 Engine Start: Equipment which is required to operate or be left switched on during engine starting shall be so identified by the equipment specification which shall also define the applicable electrical system characteristics. Equipment perf
41、ormance during engine start shall be specified by the detail equipment specification.6. LOAD DEMAND CONSTRAINTS:6.1 User Equipment Constraints :The interface characteristics of the 270 V DC Electric Power System impose the following constraints on the design of equipment utilizing DC electric power.
42、 The purpose of these constraints is to allow definition of the 270 V DC source and distribution system.6.1.1 EMC Limits: Documents defining EMC limits for users and power system shall be compatible with the power quality requirements of this document.SAE INTERNATIONAL AS1831A Page 9 of 12_ 6.1.2 DC
43、 Ripple Current Demand:The ripple current demand of each load shall be characterized. When energized from a low impedance voltage source free of ripple, the load equipment shall draw a continuous current flow with a total ripple content not exceeding an equivalent value of1000 A-Hz. The total ripple
44、 content, independent of average DC current demanded from source is defined as follows:(Eq. 1)where:I n = amplitude of individual ripple, i.e. Peak AmperesF n = frequency of the individual harmonicException to this requirement may be granted with justification.6.1.3 User Input Current Inrush/Initial
45、ization :Unless specified otherwise in the equipment specification, the instantaneous input current shall not exceed 4 times user equipment nominal full load input current, returning to equal or less than nominal full load input current within 10 ms.6.1.4 User Load Demand and Rate :All user equipmen
46、t shall be designed to control load current demand during rated operation such that its magnitude does not exceed 150% of the user equipment rated input current and the rate of change does not exceed 60 A/ms.6.1.5 User Equipment DC Ground Isolation :Each user equipment DC input power and return line at the interface shall be isolated from aircraft ground by a DC resistance of at least 10 M at 500 V DC.6.1.6 User Equipment AC Ground Isolation :The leakage capacitance to ground at the user interface shall not exceed the lower of 0.005 F/kW of connected loa
