IEC 61000-4-25-2012 pdf download.Electromagnetic compatibility (EMC) Part 4-25: Testing and measurement techniques – HEMP immunity test methods for equipment and systems.
This part of IEC 61000 describes the immunity test levels and related test methods for electrical and electronic equipment and systems exposed to high-altitude electromagnetic pulse (HEMP) environments. It defines ranges of immunity test levels and establishes test procedures. Specifications for test equipment and instrumentation test set-up, test procedures, pass/fail criteria, and test documentation requirements are also defined by this standard. These tests are intended to demonstrate the immunity of electrical and electronic equipment when subjected to HEMP radiated and conducted electromagnetic disturbances. For radiated disturbance immunity tests, specifications are defined in this standard both for small test facilities and large HEMP simulators.
This part of IEC 61000 defines specifications for laboratory immunity tests. On-site tests performed on equipment in the final installation to verify immunity are also specified. These verification tests use the same specifications as laboratory tests, except for the climatic environmental specifications.
The objective of this part of IEC 61000 is to establish a common and reproducible basis for evaluating the performance of electrical and electronic equipment, when subjected to HEMP radiated environments and the associated conducted transients on power, antenna, and input/output (I/O) signal and control lines.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60050(16 1). International Electrotechnical Vocabulary — Chapter 161: Electromagnetic compatibility
IEC 60038, IEC standard voltages
IEC 60068-1:1988. Environmental testing — Part 1: General and guidance
IEC 61000-2-5, Electromagnetic compatibility (EMC) — Part 2: Environment — Section 5:Classification of electromagnetic environments. Basic E MC publication
IEC 6 1000-2-9. Electromagnetic compatibility (EMC) — Part 2: Environment — Section 9:Description of HEMP environment — Radiated disturbance. Basic EMC publication
3 Definitions
For the purpose of this part of IEC 61000. the following definitions apply.
3.1 compatibility level specified electromagnetic disturbance level used as a reference level for co-ordination in the setting of emission and immunity limits (1EV 161-03-10)
3.2 coupling (HEMP) interaction of electromagnetic fields with a system to produce currents and voltages on system surfaces and cables
3.3 coupling clamp device of defined dimensions and characteristics for common mode coupling of the disturbance signal to the circuit under test without any galvanic connection to it
4 General
The nuclear high-altitude electromagnetic pulse test consists of two major parts: radiated immunity testing and conducted immunity testing. The radiated immunity test is performed for the purpose of demonstrating that the equipment under test has the ability to continue functioning when exposed to radiated HEMP fields. Similarly, the conducted immunity test is performed for the purpose of demonstrating that the equipment under test will not be adversely affected by exposure to conducted HEMP transients. These transients are current and voltage pulses on conductors (wires, cables) that are connected to the equipment. In general, conducted HEMP transients induced in power and telecom lines are often the most severe threats to equipment. The immunity tests described in this standard involve hazardous voltages. High-voltage precautions will be necessary to protect the health and safety of test personnel.
5 Immunity tests and immunity test levels
5.1 IntroductIon
This standard has been developed to specify the HEMP immunity test for electrical or electronic equipment and systems. The intent is to allow manufacturers to qualify equipment early in the design cycle, and to use many of the same IEC laboratory immunity tests that are already prescribed for other EMC purposes.
5.2 ImmunIty tests
HEMP immunity tests consist of two major types: radiated immunity tests and conducted immunity tests. For the purpose of this standard, the term electroriic equipments denotes an apparatus that performs a specific function. This could be a small computer or a telephone. Some equipment (for example, a computer connected to additional peripherals such as control boards to monitor processes in a factory) may be considered as part of a larger system. Often, electronic equipment are relatively small — on the order of I m x 1 m x I m or smaller. It is expected that most of the tests on such small equipment will be performed in laboratories using current injection simulators and TEM cells.
For HEMP (and EMC) tests, size can be an important factor, since very large systems may be difficult to test, especially by radiated fields. In general, radiated field tests on systems and large equipment with dimensions greater than 1 m on a side will require a large HEMP simulator. One aspect of HEMP testing that is different from other kinds of EMC testing is that there are several large (-10 m high) early-time (i < 1 ts) HEMP simulators throughout the world. It is possible to expose some systems and large equipment to the early-time HEMP threat by reproducing the pulsed electric and magnetic fields. These simulators are also useful in verifying that equipment designed and tested for HEMP survival at the equipment level, will work properly when integrated into a complete system.IEC 61000-4-25 pdf download.