Functional Design of the mCCHP-RES System - Design for Micro-Combined Cooling, Heating and Power Systems - page 255

Table 7 Requirements for supply and utility low voltage
Supply voltage characteristics
according to EN 50160 THD

Requirements for utility low voltage EN 61000 series
THD
EN 61000-2-2 EN 61000-3-2

5 % 3rd, 6 % 5th, 5 % 7th, 1, 5 %
9th, 3.5 % 11th, 3 % 13th, 0, 5 %
15th, 2 % 17th, 1, 5 % 19th, 0,5 %
21th, 1.5 % for >23th

6 % 5th, 5 % 7th,
3.5 % 11th, 3 %
13th, THDu < 8 %

5 % 3rd, 6 % 5th, 5 % 7th,
1.5 % 9th, 3.5 % 11th, 3 % 13th,
0.3 % 15th, 2 % 17th

disturbances on the supply and by other equipment in the installation, as well as
itself in uencing the supply.

These problems are summarized in the EN 61000 series of EMC standards, in
which the limits of conducted disturbances are characterized. Standard IEC 038 [ 6 ]
distinguishes two different voltages in electrical networks and installations:

supply voltage which is the line-to-line or line-to-neutral voltage at the point of
common coupling (PCC), i.e., main supplying point of installation;

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utility voltage which is the line-to-line or line-to-neutral voltage at the plug or
terminal of the electrical device.

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is equipment
that is important. The EMC standards concern the utility voltage, according to IEC
038, while EN 50160 deals with the supply voltage. The differences between these
voltages are due to voltage drops in the installation and disturbances (see Table 7 )
originating from the network and from other equipments supplied from the
installation. Because of this, in many standards of the EN 61000 series, the
equipment current is an important parameter, while this current is not relevant
according to EN 50160.
In conclusion, the electrical part of the CCHP system for on-grid operation must
satisfy the EN 50160 standard, having the main voltage parameters and their per-
missible deviation ranges at the customer

On the user ' is side, it is the quality of power available to the user '

s point of common coupling in public low
voltage (LV), under normal operating conditions. The electrical equipments,
especially the inverter, must satisfy EN 61000 series of EMC standards, having the
main voltage parameters and their permissible deviation ranges.
In short, for sizing an inverter the following conditions must be satis

'

ed:

Rated Output Capacity of inverter P output >P CHP ;

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Input Voltage of inverter V input =V CC (equal with rated batteries voltage);

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Rated Output Voltage V output : 220 - 230 V AC ;

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Total Harmonic Distortion THD : <4 %;

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Output Frequency: 50 ± 0.05 Hz.

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