Furuno WR2120, Руководство по установке

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51
APPENDIX
A.
LIGHTNING PROTECTION ASSESSMENT
A.1. Introduction
This document outlines lightning protection based on the international standard IEC (International
Electrotechnical Commission) 62305 series. The series consists of four documents as shown
below:
IEC 62305 series: Protection against lightning
IEC 62305-1:2010 Part 1: General principles
IEC 62305-2:2010 Part 2: Risk management
IEC 62305-3:2010 Part 3: Physical damage to structures and life hazard
IEC 62305-4:2010 Part 4: Electrical and electronic systems within structure
A.2. Risk Assessment
A.2.1. Evaluate the need of protection
According to IEC 62305-1, the risk shall be considered in the evaluation by protection requirements
against lightning. For each risk to be considered the following steps shall be taken:
– Identification of the components
𝑅
𝑋
which make up the risk;
– Calculation of the identified risk components
𝑅
𝑋
;
– Calculation of the total risk R;
– Identification of the tolerable risk
𝑅
𝑇
;
– Comparison of the risk R with the tolerable value
𝑅
𝑇
.
If
R ≤ x𝑅
𝑇
, lightning protection is not necessary.
If
R > 𝑅
𝑇
, protection measure shall be adopted in order to reduce
R ≤ x𝑅
𝑇
for all risks to which the
structure is subjected.
The procedure to evaluate the need for protection is given in the Figure A.1.
According to IEC 62305-2, risk components are as shown in the Table A.1.
Components Risks for weather radar Remarks
Source
of damage
𝑆
1
: flashes to the structure
𝑆
2
: flashes near the structure
𝑆
3
: flashes to the lines connected to the structure
𝑆
4
: flashes near the lines connected to the structure
Types
of damage
𝐷
3
: failure of electrical and electronic systems
Types
of loss
𝐿
2
: Loss of service to the public
𝐿
4
: Loss of economic value
𝑅
𝑇
= 10
−3
[𝑦
−1
]
Tolerance for
𝐿
2
and
𝐿
4
:
Risks
𝑅
2
: risk of loss of service to the public
𝑅
4
: risk of loss of economic values
Table A.1: Risk components (IEC 62305-2)