IEEE Std C57.637 pdf free download
IEEE Std C57.637 pdf free download.Mineral Insulating Oil and Criteria for Its Use.
4. Classification of service-aged oils and criteria for reuse
4.1 General classification of service-aged oils
The functional limits of oil properties in different apparatus vary with the type and design so that the acceptable limits for oils that can remain in service arc dependent upon the requirements of the specific apparatus. Suggested limits for oil remaining in service at various voltage classes are given in IEEE Std C57. 1 O6T1. It is therefore impossible to indicate the significance of specific tests and recommended test limits for all possible existing applications of in-service insulating oil. It should also be recognized that no one test can be used as the sole criterion of the condition of oil in service. It is possible, however, to summarize the value and importance of current tests and to suggest methods of treatment for the oil being examined, such methods being based on current industry experience.
4.2 Suggested limits for classes of service-aged oils
The suggested limits for mineral oil after equipment filling but before energizing. at various voltage classes, are given in IEEE Std C57.106. It is not intended that oil be removed from service when a single property limit is exceeded or that the oil be left in service until all property values arc outside the stated limits. Each ca.ce should be examined individuall)’ arid manufacturer ‘s advice mar he considered.
Oils that do not meet the suggested limits for continued service in their respective voltage classes may be considered for reuse in similar apparatus operating at a lower voltage class if they meet the limits for that class, or they may be suitable for reconditioning (Group I) or reclamation (Group II). Suggested limits for oils in these groups are contained in Table 1. Oils that do not meet the suggested limits for Group II should be discarded unless the reclamation process in use can restore the oils to the limits given in Table 2. Table 2 provides suggested requirements for reclaimed mineral oil for use in transformers prior to filling the equipment. Properly reclaimed oil meeting the minimum requirements of Table 2 may contain excessive quantities of water and dissolved gases for use in some transformers and should, therefore, be subjected to additional processing during filling, such as vacuum dehydration if required, to comply with the apparatus manufacturer’s specification limits for water.
4.4 Sources of oil to be reclaimed
Suggested sources of oil for reclamation include transformers, reactors, voltage regulators, circuit breakers, and reclosers. Insulating fluid from cables, capacitors, generators, or devices filled with non-mineral insulating oil are not included in the scope of this guide. It is common practice to collect and store reclaimable oil from a variety of sources until a sufficient quantity is accumulated to reclaim as a batch. The nature of contaminants remaining in such pooled oil after reclamation is much more unpredictable than those from a single source, so the reuse of this pooled oil should be restricted to apparatus with less stringent oil requirements.IEEE Std C57.637 pdf download.
