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SECTION 4 |
Parameter "SYNC GRID" is used to program the desired sensitivity of frequency and phase synchronization of the
Inverter Section with the AC input voltage fed at the AC Input Terminals marked "GRID" (4,5,6 in Fig 2.3 in Owner's
Manuals for (i) EVO-2212/3012/2224/4024 and (ii) EVO-2212E/3012E/2224E/4024E).
2 programming options are available for this parameter: (i) Option "0= Fine" (Default option) – see Section 4.5.2.9(a)
below and (ii) Option "1= Coarse" – see Section 4.5.2.9(b) below.
When EVO-2212/ 2212E / 3012 / 3012E / 2224 / 2224E / 4024 / 4024E is operating in Inverting Mode (there is no
AC input), its output frequency will be equal to the frequency that has been selected by the programming parameter
"DEFAULT FREQ" (TABLE 4.6 and Section 4.5.2.1). When AC input is made available at AC Input Terminals marked "GRID"
(4,5,6 in Fig 2.3 in Owner's Manuals for (i) EVO-2212/3012/2224/4024 and (ii) EVO-2212E/3012E/2224E/4024E), it is
first monitored for 2 sec. If it is within the programmed values of (i) frequency limits (TABLE 4.6), (ii) low voltage limits
(TABLE 4.7) and (iii) high voltage limits (TABLE 4.8), synchronization process is initiated to synchronize the frequency and
phase of the Inverter Section with the incoming AC input voltage. Details are given below:
a) Parameter "SYNC GRID" set at Option "0= Fine" (Default)
This is the "Default Setting". This setting is applicable when Grid / Inverter Generator is connected
to AC Input Terminals marked "GRID" (4,5,6 in Fig 2.3 in Owner's Manuals for (i) EVO-
2212/3012/2224/4024 and (ii) EVO-2212E/3012E/2224E/4024E). Synchronization control logic used
in this option is suitable for more stable frequency output of Grid / Inverter Generator. Under this
option, the frequency and phase of the Inverter Section are synchronized with the Grid as follows:
i.
ii. Then, the phase of the Inverter voltage relative to the Grid voltage is tracked by 1º per cycle.
Parameter SYNC GRID set at Option 1= Coarse
This setting is selected if a Generator is connected to AC Input Terminals marked "GRID"
(4,5,6 in Fig 2.3 in Owner's Manuals for (i) EVO-2212/3012/2224/4024 and (ii) EVO-
2212E/3012E/2224E/4024E). As compared to very stable frequency of Grid / Inverter Generator,
the frequency of a Generator may vary considerably depending upon the performance of its Speed
Governor that compensates for the drop in RPM / frequency when electrical load is switched on
/ increased or, rise in RPM / frequency when electrical load is decreased /switched off. Hence, if
synchronization sensitivity set is at "0= Fine" as in Section 4.5.2.9 (a) above, it may take very long
for the Inverter Section to synchronize with the Generator or, may not synchronize at all. Under
this option, the frequency and phase of the Inverter Section are synchronized with the Generator
differently as follows:
i.
ii. Then, the phase of the Inverter voltage relative to the phase of the Generator / Inverter
84 | SAMLEX AMERICA INC.
Parameter Setup
First, the frequency of the Inverter Section is tracked in steps of 0.1Hz per cycle and made
equal to the frequency of the Grid / Inverter Generator input.
When the phase of the Inverter voltage is within ± 3.5º of the input voltage waveform, the
Transfer Relay is activated to transfer the AC load from the Grid / Inverter Generator to the
Inverter Section at zero crossing of the voltage waveform.
First, the frequency of the Inverter Section is NOT tracked at 0.1Hz per cycle as in Option "0=
Fine" [See Section 4.5.2.9(a) above] but is made equal to the Generator frequency at zero
crossing of the Inverter voltage.
Generator voltage is tracked by 1º per cycle. When the phase of the Inverter Section is within
± 10.5º of the Generator input voltage waveform, the Transfer Relay is activated to transfer the
AC load from the Generator to the Inverter Section at zero crossing of the voltage waveform.
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