Connecting a substation to the Enel Colombia grid takes more than working equipment: it has to fit the distribution company's technical standard and pass its design review. The compact substation CTS596 helps with that by delivering medium-voltage switchgear, a transformer and a low-voltage board on a single frame. Here we explain what the standard requires, what changed between 2025 and 2026, and how to specify it properly.
A compact substation is a prefabricated assembly that brings medium-voltage switchgear, the transformer and the low-voltage board together on one metal frame. The compact substation CTS596 arrives assembled, is placed in the substation room and is connected by medium- and low-voltage cable. The alternative is a conventional substation, where each piece of equipment is installed separately and interconnected on site.
Enel Colombia (formerly Codensa) publishes its construction standards on the Likinormas portal. CTS596 is the standard for the "prefabricated transformation center inside buildings". It defines configurations, components, grounding, internal arc protection and oil containment. In other words, it tells the manufacturer what the assembly must include for the utility to accept it.
One fact worth getting right when you specify: according to the Enel Colombia portal, the current CTS596 is Revision 2, effective October 3, 2025, and it covers transformers up to 1000 kVA. The earlier title of the standard referred to up to 400 kVA (the portal's web address still carries it). So every compact substation CTS596 model from 75 to 400 kVA remains within range, but they are no longer the ceiling of the standard.
The standard provides for nine configurations, depending on power rating (up to 225 kVA, above 225 up to 630 kVA, and above 630 up to 1000 kVA) and on the number of line positions (L) and transformer protection positions (T): 2L+1T, 3L+1T and 4L+1T.
Key CTS596 Rev. 2 requirements (source: Enel Colombia)
The compact substation CTS596 also calls for a telecontrol board with auxiliary services and metering, and a low-voltage protection board. Two useful clarifications: the make and technology of the switchgear are chosen by the manufacturer within Enel Colombia's specifications, and the standard does not detail a routine test or commissioning protocol. That is why it pays to agree on that protocol with the manufacturer and the inspection body from the quotation stage.
According to the Ectricol datasheet, the MB CTS compact substation is designed to CTS596 and offered as a "plug and play" solution from 75 to 400 kVA. Its components are:
Specification lesson. Before ordering the compact substation CTS596, confirm three things with the manufacturer in writing: the CTS596 revision the design was validated against, the factory test protocol and the internal arc classification of the assembly. The public datasheet does not detail them, and it is best to have them documented before the design review.
Assembling the compact substation CTS596 at the factory reduces the activities that depend on the job site: there is no need to mount and wire each piece of equipment separately, and oil containment comes built into the frame. What does not change is the process: according to Enel Colombia's project submission guide (2025), design review has a response time of 7 business days for low voltage and 15 business days for medium voltage, counted from complete documentation. A design that already follows the standard can lower the risk of rejections.
The current RETIE is Resolution 40117 of 2024, amended by Resolution 40284 of 2026 (issued on June 23 and published on July 1). Under that resolution, works started on or after January 1, 2026 can no longer demonstrate compliance under Resolution 90708 of 2013. In practice, the compact substation CTS596 and the installation must hold the certification and inspection required by the current regulation.
The compact substation CTS596 is intended for buildings that need their own transformer inside the premises, and its selection is always tied to the engineering of each project. You can see the MB CTS compact substation datasheet on our site. The original standard can be consulted on the Enel Colombia Likinormas portal.
It is the technical standard for the prefabricated transformation center inside buildings. Its Revision 2 has been in force since October 3, 2025 and covers transformers up to 1000 kVA.
Yes. The project goes through feasibility and design review. Enel Colombia's guide states a response in 7 business days for low voltage and 15 business days for medium voltage, counted from complete documentation.
The compact unit combines switchgear, transformer and low-voltage board on a single frame assembled at the factory. A conventional substation is installed piece by piece and interconnected on site.
The standard requires containing 100 % of the oil with a drain valve and using high fire-point oil. Ectricol offers the transformer in mineral or vegetable oil.
The current one: Resolution 40117 of 2024, amended by Resolution 40284 of 2026. Since January 1, 2026, Resolution 90708 of 2013 no longer applies to new works.
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