Shell MIDEL Ester Transformer Fluids
Enabling safer, more reliable power networks
Shell MIDEL transformer fluids combine fire resistance1 with ester base oils that meet ready biodegradability criteria, as determined by OECD 301 test methods. Compared with conventional mineral oils, their biodegradability profile may help reduce the persistence of the trasnformer fluid following an accidental leak or spill into aquatic environments, while supporting reliable transformer protection (EPA Publication 800-R-11-002).
Key benefits
Uncompromising fire safety
Classified as K Class, with high fire and flash points, these fluids are less flammable, which can prevent a transformer fire from spreading and save the surrounding property, people and environment.1
Biodegradability Profile
The base oils used in the Shell MIDEL ester fluids are readily biodegradable according to OECD 301 test criteria, breaking down faster than conventional mineral oil. The Shell MIDEL range of ester transformer fluids include synthetic and natural bio-sourced esters.3
Helps save costs
The fire safe properties of Shell MIDEL make it possible to reduce substation footprint and costs (both construction and insurance) that can arise from fire protection measures.6
Cold weather performance
Extremely low pour points, down to −56°C, deliver a highly effective solution for colder-climate installations.7
Improved moisture tolerance
Shell MIDEL ester transformer fluids absorb far more moisture than conventional mineral oils without compromising their dielectric properties, which can help to protect the integrity of the solid insulation.7
Longer asset life
Hotter running and sustainable overloading can help improve transformer reliability, delivering longer asset life and business continuity assurance.7
Shell MIDEL 7131
Synthetic ester fluid
Shell MIDEL 7131 K3 class is specifically formulated to be a fire-safe,¹ high-performance fluid providing all the benefits of ester technology. It is the fluid of choice when the performance demands on the transformer are higher, especially if located in a cold climate (it has a pour point of −56°C)7 or when there is a risk of contact with air. Shell MIDEL 7131 is also ideal for transformers located indoors, outdoors or underground, and for high temperature, breathing-type equipment. It has a long track record in demanding applications such as wind turbines and rolling stock and is proven over 400 kV.2
Shell MIDEL 7131 meets the IEC 61099 and ASTM D8240 standards.
Shell MIDEL eN 1204
Rapeseed/canola natural ester fluid
Shell MIDEL eN 1204 is a K2 Class bio-sourced dielectric fluid5, and made from readily biodegradable base oils according to OECD 301 test criteria. Its pour point of −31°C7 makes it an effective fluid for installations in cooler climates. It has a high fire point of over 350°C,7 increasing the fire safety of transformers, and can reduce the need for fire protection equipment. Like all natural ester transformer fluids, Shell MIDEL eN 1204 is best suited for use in non-breathing equipment.
Shell MIDEL natural esters meet IEC 62770, IEEE C57.147 and ASTM D6871 standards.
Shell MIDEL eN 1215
Soybean natural ester fluid
Shell MIDEL eN 1215 is formulated from soybean oil. This product is an efficient general-purpose fluid, ideal for a wide range of transformers located indoors or outdoors. Shell MIDEL natural esters meet IEC 62770, IEEE C57.147 and ASTM D6871 standards.
Shell MIDEL Regen
Derived from in-service Shell MIDEL 7131 synthetic ester fluid, Shell MIDEL Regen delivers the same proven transformer performance and fire-resistant properties as Shell MIDEL 7131, together with synthetic ester base oil chemistry that meets ready biodegradability criteria under OECD 301 test methods.
Applications
Having been first introduced to industry in the 1970s,9 Shell MIDEL ester transformer fluids are trusted in a wide range of mainstream large power and distribution applications,2 including:
Utilities
Mining and Underground
Renewables
Data Centres
Rail
Marine
Offshore and Subsea
Commercial and Industrial
1 Shell MIDEL 7131 meets IEC 61099 and ASTM D8240 specifications, K3 Class. Shell MIDEL eN 1204 and Shell MIDEL eN 1215 meets IEC 61039 and ASTM D6871 specification, K2 Class. K classification transformer liquids have a high fire and flash point, and are less flammable. These properties can prevent a transformer fire and help save property, people and the surrounding environment. FM Approved, UL classified.
2 Shell MIDEL internal research and customer data.
3 Shell MIDEL eN 1204 and Shell MIDEL eN 1215 each have 100% biobased carbon content. Both are tested according to the ASTM D6866-21 method. Reported results are accredited to ISO/IEC 17025:2017 Testing Accreditation PJLA #59423 standards, and all chemistry was performed at Beta Analytic testing laboratory and counted in its accelerators in Miami, Florida, August 2021.
5 Shell MIDEL eN 1204 and Shell MIDEL eN 1215 each have 100% biobased carbon content. Both are tested according to the ASTM D6866-21 method. Reported results are accredited to ISO/IEC 17025:2017 Testing Accreditation PJLA #59423 standards, and all chemistry was performed at Beta Analytic testing laboratory and counted in its accelerators in Miami, Florida, August 2021.
6 May reduce insurance premiums due to proven fire safety and FM Approval. Potential reduction in fire barriers leading to cost reductions for construction and land space. Can reduce asset downtime related to fire issues and moisture ingress. Advice should not override countries’ local legislation and laws.
7 Shell MIDEL 7131 meets IEC 61099 and ASTM D8240 specifications. Shell MIDEL eN 1204 and eN 1215 meet IEC 62770 and ASTM D6871 specifications.
8 FM Global, an international insurance carrier, provides a certification mark called FM Approvals through its independent testing arm. Safety products must be tested and approved before they are sold to the public. Underwriters Laboratories, a non-profit testing facility headquartered in Northwood, Illinois, is one of the organisations responsible for testing and approving these types of products.
9 Shell MIDEL 7131 was first launched in 1978 and is specified and used by transformer manufacturers and utilities worldwide. In 2023, the MIDEL brand was acquired by Shell and is now known as Shell MIDEL.
