In some data center power system designs, UPS does not require any transformers to be used; But in many cases, it is necessary or recommended to install transformers in combination with UPS. This article will introduce that there are 92 different transformer combinations available for a UPS system, and there are even more combinations that can be used in conjunction with parallel or other redundant configurations. If the important differences between various alternative solutions cannot be understood, the use of transformers in UPS systems cannot be studied. The configuration of UPS systems is divided into three basic categories based on whether there is a static bypass and its connection method. These three categories are commonly referred to as single input, dual input, and bypass free single input.
① In a single input device, a bypass and UPS module connected to the UPS are powered together by an input connection. This is the most common built-in method and the only organizational method supported in many small UPS systems. The primary advantage of this type of system is its simplicity, low cost, and the absence of many complex elements related to current circulation and grounding. This type of organization is found in both large and small data center equipment, as well as many large data center equipment. The drawback of this type of system is that the practical input power supply system cannot be blocked for protection under the condition of power outage to critical loads, although some unfavorable factors can be overcome through the surrounding circuit breaker on the input.
② When the bypass route is different from the input that supplies power to the UPS rectifier, a dual input equipment is required. The difference in input can be small (e.g. powered by different circuit breakers on the same panel) or large (e.g. they come from completely independent power sources with different grounding systems and even voltages). There are various redundant architectures in data centers that require the use of such equipment. Another reason for using dual input equipment is to be able to disable either input for protection when supplying power to critical loads. It should be noted that this equipment can be used when using a generator, but it is not necessary because the generator is usually connected to the upstream of the UPS input bus through an automatic transfer switch (ATS) to supply power to both the UPS and other loads (such as chillers). Dual input equipment is necessary in some data center architectures and is used as a preferred plan for many larger data centers to achieve parallel protection and/or slightly improve the overall reliability of the system, as it can avoid the upstream connections and circuit breakers of the UPS becoming a single point of failure in the power system. The sentence is:.
③ The last type of equipment without bypass single input is primarily used in environments where the input power quality is considered extremely poor and where it is determined that it is no longer suitable to supply critical loads through bypass input. This may occur in industrial applications, ships, or small islands where the input frequency (50 or 60Hz) is different from the I load frequency, or perhaps in developing country home appliance networks with high power supply pressure. In some countries, this is an extremely rare method, while in some countries (such as India) it is common and even accounts for the majority of installed equipment in certain regions.