Solar Lattice

Constant power factor mode

ID: func:constant-power-factor
IRI: https://solarlattice.org/kb/func/constant-power-factor
Status: active
Also known as: fixed power factor, cos phi fixed, PF mode, DFPF, Fixed PF, Fixed Power Factor mode
Category: Grid support
Function kind: grid-support

Constant power factor mode makes the inverter run at a fixed power factor, so its reactive power follows its active output at a set ratio. In FIMER Aurora Manager LITE, you pick cos-phi fixed as the reactive power regulation mode, enter the over- or under-excited value and confirm with SET. CPS SCH125KTL-AIO, SCH200K/SCH250K-T, SCA25KTL-DO and CSI 23/28KTL-CT inverters list power factor adjustable to plus or minus 0.8. The FIMER PVS-166 adjusts to 0.75 lead or lag, the PVS-175 to 0.8, and the UNO-DM-3.3/3.8-PLUS to plus or minus 0.8.

<!-- review notes

sentence 1: support check: partial - Constant PF operation is stated, but the reactive power following active output at a set ratio is an inference not explicitly stated.
sentence 2: support check: partial - Selecting cos-phi fixed, entering over/under-excited value and confirming with SET are stated, but the passages don't name Aurora Manager LITE.
sentence 1: review: partial - The passages state operation at a constant or fixed power factor, but the claim that reactive power follows active output at a set ratio is an inference the passages do not state. -->

Claims

`response_time`

c1 drafted · lead ≤ 10 SEC

Scope: standard IEEE 1547-2018 proposed

Conditions: Maximum DER response time to maintain the constant power factor

The maximum DER response time to maintain constant power factor shall be 10 s or less.
— IEEE 1547-2018 §5.3.2. Quoted with attribution; the text remains the publisher's copyright.

IEEE 1547 - 2018 [code/standard] sec=5.3.2 h=6aaf1eecb7b8

`setting_range`

c2 drafted · lead 0–1 UNITLESS

Scope: standard IEEE 1547-2018 proposed

Conditions: Constant Power Factor setting parameter; excitation set separately as over- or under-excited

IEEE 1547 - 2018 [code/standard] tbl=37 h=75588dc5dd29
IEEE 1547 - 2018 [code/standard] tbl=37.r2 h=ee76f3623026

c3 drafted · lead 0.8–1 UNITLESS

Scope: products Solis S6-EH2P(9.6-16)K-SV-YD-L-US

Conditions: Power Factor Setting Value (Modbus register 43054); allowed bands are -1 to -0.8 and +0.8 to +1

Solis_manual_S6-EH2P(9.6-16)K-SV-YD-L-US_V2.7_20260305 tbl=26 h=bc62159b4750
Solis_manual_S6-EH2P(9.6-16)K-SV-YD-L-US_V2.7_20260305 tbl=26.r2 h=4adf0ad1c7cd

c5 drafted · lead ≥ 0.8 UNITLESS

Scope: products CPS SCH125KTL-AIO/US-600, CPS SCH200K-T-US-480 / SCH250K-T-US-600, CPS SCA25KTL-DO/US-208, CSI 23/28KTL-CT/US-480

Conditions: Power factor adjustable to 0.8 leading or lagging (listed as plus/minus 0.8 adjustable); nominal power factor above 0.99

CPS SCH125KTL-AIO-US-600 Sep 2020 tbl=37.r19 h=14255a5f7bdd
CPS SCH200-250K-T-US User Manual Aug 2026 tbl=45.r22 h=75c28bcd594f
CPS SCA25KTL-DO-US-208 User Manual Rev 1.2 tbl=55.r22 h=04b64ff5ef58
CSI 23-28KTL-CT Inverter Installation Manual tbl=32.r10 h=ad5edc9d8ce8

c6 drafted · lead ≥ 0.75 UNITLESS

Scope: products FIMER PVS-166/175-TL-US string inverter

Conditions: PVS-166-TL at Smax: adjustable from 0.75 lead to 0.75 lag; nominal power factor above 0.995

FIMER PVS-166-175-TL-US A.2 Product Manual RevE tbl=9.r33 h=ec1fe0973d6f

c7 verified · fact ≥ 0.8 UNITLESS

Scope: products FIMER PVS-166/175-TL-US string inverter

Conditions: PVS-175-TL at Smax: adjustable from 0.8 lead to 0.8 lag; nominal power factor above 0.995

FIMER PVS-166-175-TL-US A.2 Product Manual RevE tbl=9.r33 h=ec1fe0973d6f

verified by: review-workflowverified on: 2026-10-24

`default_value`

c4 verified · fact nominal 1 UNITLESS

Scope: products Solis S6-EH2P(9.6-16)K-SV-YD-L-US

Conditions: Power Factor Setting Value (Modbus register 43054); the Fixed PF mode enable itself defaults to Disable

Solis_manual_S6-EH2P(9.6-16)K-SV-YD-L-US_V2.7_20260305 tbl=26 h=bc62159b4750
Solis_manual_S6-EH2P(9.6-16)K-SV-YD-L-US_V2.7_20260305 tbl=26.r2 h=4adf0ad1c7cd

verified by: review-workflowverified on: 2026-10-24

Referenced by

OND file related_to c3
Power factor related_to c4
Utility power factor penalty related_to c4
Reactive power related_to c6
FIMER PVS-166/175-TL-US string inverter implements c15
UNO-DM-3.3/3.8/4.6/5.0-TL-PLUS-US string inverter implements c6
CSI 23/28KTL-CT/US-480 implements c7
CPS SCA25KTL-DO/US-208 implements c16
CPS SCH125KTL-AIO/US-600 implements c11
CPS SCH200K-T-US-480 / SCH250K-T-US-600 implements c4
CPS SCH350KTL-DO/US-800 implements c14
Fronius Galvo 208-240 implements c6
Schneider Electric Conext CL125 implements c16
Sungrow SG200HX-US implements c25
Solectria XGI 1500-1MW implements c13

Data