Furse Total Solution to Earthing & Lightning Protection

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Total Solution to Earthing & Lightning Protection |

9AKK106354A3360

Specific systems protection

Introduction

Photovoltaic (PV) systems are at risk from transient

overvoltages which may enter the system following a

direct lightning strike to a structural LPS, or via the wider

electrical network.

Protection against transient overvoltages is achieved through

installation of appropriate SPDs on the DC and AC side

of the DC-AC inverter in the PV system. Installation should

follow the guidance provided in Technical Specification

DD CLC/TS 50539-12.

Installation on the DC side of the DC-AC inverter

An SPD specifically designed for use on the DC side of a PV

system should be installed. Where the distance between the

PV array and the inverter is < 10 m, a single SPD suffices,

mounted as close as possible to the inverter. Where the

distance > 10 m, two SPDs should be installed, one close to

the inverter and the other close to the PV array. The minimum

Type of SPD is dependent on presence of structural LPS/

separation distance (see Table 4).

Table 4:

SPD requirement according to structural LPS configuration

Status of

DC side, distance PV array to inverter

Structural LPS

< 10 m

> 10 m

AC side of inverter

No structural LPS

ESP PV Series protector

ESP AC mains power protector

(min. Type 2 performance)

Structural LPS (separation distance kept)

ESP PV Series protector

ESP WT Series protector

ESP AC mains power protector

(min. Type 2 performance)

(min. Type 2 performance - inverter)

(min. Type 1 performance - MDB)

Structural LPS (separation distance not kept)

ESP PV Series protector

ESP AC mains power protector

(min. Type 1 performance)

Installation on the AC side of the DC-AC inverter

The presence (or lack) of a structural LPS, plus whether

sufficient separation distance has been kept between the LPS

and the PV array, defines the SPD requirement on the AC

side of the inverter (see Table 4). Where the distance between

service entrance (Main Distribution Board (MDB)) and inverter

is < 10 m, a single SPD should be installed at the service

entrance (MDB). Where > 10 m, two SPDs should be

installed, one at the MDB and the other close to the inverter.

Furse Combined Type SPDs for AC mains power circuits are

applicable here. The SPD to be installed will be dependent

on the Class of LPS around the structure, and the location of

the metallic services connected to it (i.e. underground/

exposed overhead supply).

Generator junctionbox -SPD for

PV systems (ESPDC550/12.5/PV)

SPD forACmains

power (Combined

Type1+2)

Operationbuilding -SPD

forPV systems (ESPDC1000/12.5/PV)

PVunits

LPZ0

Roof mounted PV array, with external LPS

IMPORTANT:

This page refers to protection of PV power circuits only. Ensure any data/signal/

telecoms lines connected to the PV system are also appropriately protected.

NOTE:

Furse ESP PV Series SPDs offer combined Type 1+2 protection, and therefore apply

across all scenarios.

SPD

SPD for PV systems

(ESP DC550/12.5/PV or

ESP DC1000/12.5/PV)

Output

Equipotential

bonding bar

Input

kWh kWh

SPD

SPD for AC mains power

(Type 2 - separation distance kept)

(Type 1 - separation distance

not kept)

SPD for AC

mains power

(Type 1)

LV Incomer

Earthing

conductor

External LPS

s = separation distance.This installation shows the separation distance is kept.Where the

separation distance is not kept, the PV array should be bonded directly to the external LPS.

Earth

termination

system

Meter/main

distribution

Protection of solar park/PV array