Ingeteam INGECON SUN FSK C Series: Solar Power Station

What it is and where it is used

Ingeteam, a Spanish manufacturer headquartered in Sarriguren (Navarra), offers the PowerStation INGECON SUN FSK C Series as a medium-voltage transformer station for 1500 V solar plants. The FSK (Full Skid) is delivered premounted on a steel base, with up to two INGECON SUN 3Power C central inverters, the step-up transformer, the medium-voltage switchgear and the auxiliary services. Ingeteam offers it in IEC and UL versions.

The PV array arrives as direct current at the inverters (central inverter architecture), normally through string combiner boxes, and the station delivers at medium voltage to the collector network, which ends at the plant’s step-up substation. All equipment is suitable for outdoor use, so there is no building or container. In the plant architecture shown in the datasheet, the plant controller and SCADA are outside the station, at the point of connection.

Variants: 3825 FSK C Series and 7650 FSK C Series

The powers in the table are calculated by Ingeteam with the INGECON SUN 3825TL C690 inverter; they change with other models of the C series.

Main features

According to the PowerStation FSK C Series 1,500 Vdc datasheet:

• Inverters: one or two INGECON SUN 3Power C, with an IP65 power stage and combined water and air cooling, their own electrical protections and grid support functions (voltage ride-through, reactive power and active power control).
• Transformer: oil-filled, hermetically sealed, 36 kV class, 50 or 60 Hz, ONAN cooling (KNAN as an option) and a minimum peak efficiency index of 99.50 %. For Europe, ecodesign according to EU regulations 548/2014 and 2019/1783.
• Medium-voltage switchgear (RMU): 24 or 36 kV, 630 A, natural ventilation and IP54; 2L1A configuration as standard (0L1A1L, 1L1A and 0L1A as options). The product page also includes a 40.5 kV option.
• Auxiliary services: self-powered IP54 auxiliary services panel and, as an option, an auxiliary services transformer of up to 60 kVA, Dyn11.
• Other: oil retention pit, frame for the low-voltage equipment, medium-voltage surge arresters and an Ethernet or fiber switch as options, and an energy meter as an accessory.
• Environment: operation from −5 °C to 50 °C and up to 4500 m, with derating from 1000 m.
• Stated standards: IEC 62271-202, IEC 62271-200 and IEC 60076.

The INGECON SUN 3825TL inverter (3Power C Series)

The C series datasheet describes a three-phase transformerless central inverter, with 1500 V technology, a single power stage, a single MPPT tracker and power of up to 3.8 MVA. Its variants are identified by the nominal AC voltage, which goes from C600 (600 V) to C690 (690 V) in an IT system:

(The datasheet also lists C615, C630, C645 and C675.) Common to all: maximum DC voltage of 1500 V, maximum DC current of 3965 A and up to 24 inputs with fuse holders. The output current is 3200 A at 35 °C and 2750 A at 50 °C. The power factor is adjustable from 0 to 1 (leading or lagging) for output power above 25 % of nominal. THD (total harmonic distortion) is below 3 %, maximum efficiency is 98.9 % and CEC efficiency is 98.5 %. The maximum DC voltage must account for the rise in Voc at low temperature, as the datasheet itself indicates.

More data from that datasheet:

• Cooling. A closed liquid circuit (biodegradable glycol and water mixture) for the IGBTs and the power phases, and a water-to-air exchanger that cools the air of the IP65 compartment. The rest of the equipment uses temperature-controlled forced air. The LC filter and the exchanger are IP54.
• Stated grid functions: voltage ride-through, fast frequency regulation, reactive power at night, voltage droop control, active power reserve without batteries, grid-following and grid-forming operation, black start capability and automatic voltage regulation.
• Communication: dual Ethernet port to the SCADA and the plant controller, and Wi-Fi as an access point for commissioning and maintenance.
• Protections: DC reverse polarity, output short circuit and overload, anti-islanding with automatic disconnection, DC insulation fault, motorized DC disconnect and motorized AC breaker.
• Operating conditions: from −20 °C to +60 °C (with a heater kit, from −40 °C to +60 °C). Maximum altitude of 4500 m, with consultation with the manufacturer from 1000 m. Noise of 49.6 dB(A) at 10 m, which the equipment adjusts according to operating conditions.
• Stated standards: IEC 62109-1 and -2, IEC 62116, IEC 61683, EN 50530, IEC 61727 and EN 50549-2, plus grid profiles for several countries, among them Brazil (Submódulo 2.10) and Mexico (CRE). For other codes, Ingeteam asks to consult additional certificates.

A point to clarify with the manufacturer. The FSK datasheet states 3658 kVA at 35 °C per inverter. It says it calculated that figure with the 3825TL C690 model, but the C series datasheet lists 3824 kVA for the C690 and 3658 kVA for the C660. It may be due to a station limitation or to a difference between documents; the exact power of each configuration should be requested from Ingeteam in writing when specifying. On the string combiner box side, the FSK offers as an option INGECON SUN StringBox units of 16, 24 or 32 channels, smart or passive, and as further options grounding of the PV array and reactive power regulation when there is no PV power.

Protection of the transformer switchgear

The single-line diagram in the datasheet shows, in the transformer position, a relay with functions 50, 51 and 50N, on the switchgear that feeds the step-up transformer. The datasheet does not detail whether that position is a breaker or a combined fuse, nor the own protections of the sealed transformer that are wired to the trip; that is confirmed in the detailed engineering of the project. An integral-fill transformer, with no conservator, does not use a Buchholz relay: its gas, pressure and temperature signals are taken with its own device.

The relay coordinates with the collector feeder at the substation. The protections of the plant connection (anti-islanding, transfer trip) are at the point of connection.

Communications and integration

The datasheet includes as an option an Ethernet or fiber optic switch in the station, to form the plant network. Supervision of the inverters and the station is integrated into the plant SCADA, and power setpoints arrive from the power plant controller (PPC), which the datasheet places at the point of connection, outside the scope of the station. Ingeteam lists its INGESYS SMART SCADA as a related product.

What is checked at commissioning

In general terms: inspection of the skid and its grounding. Transformer tests. Verification of the sealed transformer’s signals to the switchgear trip. Secondary injection to the 50/51/50N relay. RMU interlocks and gas. Auxiliary panel and transformer. Communications. Energization from the collector network and start-up of the inverters.

Frequently asked technical questions

• Datasheet: Ingeteam publishes the FSK C Series datasheet on its product page; custom configurations are requested from the manufacturer.
• IEC or UL version: the IEC version states IEC 62271-202, 62271-200 and 60076; the UL version follows North American standards.
• Inverter: the grid functions and the grid code profile are defined by the 3Power C; the local grid code requirements are demonstrated for the complete plant.

How we can help

At Tiza Group we carry out the testing and commissioning of medium-voltage stations and of the complete plant: transformer, RMU and relay, own protections, communications and energization, in Colombia or elsewhere on request. See the scope in solar plant testing and commissioning. For the coordination of the station relay and the engineering, see engineering design and studies. To request a quotation, write to us through contact.

Related guides

• Solar transformer station (skid): what it is and its parts
• Central or string inverter in solar plants: architecture
• Step-up substation of a solar plant
• Protection of a solar plant
• Solar plant commissioning tests
• Power Electronics MV Skid Compact and Twin Skid Compact
• Sungrow MVS6400-LV, MVS8960-LV and 1+X SG6600UD-MV

References

• Ingeteam, PowerStation FSK C Series 1,500 Vdc datasheet.
• Ingeteam, INGECON SUN FSK C Series product page.
• IEC 62271-202, high-voltage/low-voltage prefabricated substations.
• IEC 62271-200, AC metal-enclosed switchgear and controlgear.
• IEC 60076, power transformers.

Frequently asked questions