Question

Explain the load balance of UPS in a given data center power design (how loaded each of UPS is as compared to its rated capacity.

Answer 1

When sizing UPS it is important to know the phase configuration required by both the mains supply and the loads, in addition to the overall load size. Electrical experts will often state both load size and phase configuration. An example would include ‘120KVA three phase’. This refers to a 120KVA load run from a three phase 415Vac, 50Hz supply. In terms of load sizing, this means that each phase (of the 3 phase electrical supply) will deliver upto 40KVA (or 174Amps at 230Vac). If the statement was 120KVA per phase then we would be looking at 3×120KVA per phase = 360KVA UPS load. The need for a 120KVA three phase UPS could be met with three single phase output 40KVA UPS provided the connected loads are single phase loads. These would be 3/1 configured and installed one per phase. However, the overall capital, installation and energy efficiency costs just rose by a factor of 3 compared to a single 120KVA UPS system installation. 3/1 UPS upto 60KVA are also used in office environment where the loads are single phase and this removes the need to balance the load connections in each of the three phases. Larger 3/1 UPS even upto 200KVA are typically required for DCS and SCADA loads in heavy industries like Power Plant, Steel Plant etc.

UPS Sizing steady state load conditions

Steady state loading conditions

As like any other power source, UPS is a limited power supply and the capacity of the UPS is defined in KVA(apparent Power) and KW (real power).

To arrive at the capacity of UPS and the configuration of UPS, the following steps needs to be followed

• Step 1 Need of Load
• Step 2 Configuration of UPS
• Step 3 Check on the KVA & KW demand supplied by the UPS

Step 1: Need of Load

The load demand of the loads expected to be connected to the UPS.

(Note: The load power factor has to be measured at the site or can be assumed based on the past experience)

Step 2: Configuration of UPS

The criticality, of the loads will determine the necessary availability of the UPS. Based on the criticality the UPS capacity or configuration can be selected.

Where N is the number of UPS, required to support the Load. For critical load with 66% redundancy N>2, where a minimum of 2 UPS is required to support the load and 1 UPS for redundancy

Step 3: Selecting the required UPS capacity

Based on the total demand and the configuration of UPS, the capacity of UPS is selected. The total load in KVA and KW derived in step 1 will have to divided by N as selected in step 2 to arrive the UPS capacity.

Answer 2

When sizing UPS it is important to know the phase configuration required by both the mains supply and the loads, in addition to the overall load size. Electrical experts will often state both load size and phase configuration. An example would include ‘120KVA three phase’. This refers to a 120KVA load run from a three phase 415Vac, 50Hz supply. In terms of load sizing, this means that each phase (of the 3 phase electrical supply) will deliver upto 40KVA (or 174Amps at 230Vac). If the statement was 120KVA per phase then we would be looking at 3×120KVA per phase = 360KVA UPS load. The need for a 120KVA three phase UPS could be met with three single phase output 40KVA UPS provided the connected loads are single phase loads. These would be 3/1 configured and installed one per phase. However, the overall capital, installation and energy efficiency costs just rose by a factor of 3 compared to a single 120KVA UPS system installation. 3/1 UPS upto 60KVA are also used in office environment where the loads are single phase and this removes the need to balance the load connections in each of the three phases. Larger 3/1 UPS even upto 200KVA are typically required for DCS and SCADA loads in heavy industries like Power Plant, Steel Plant etc.

UPS Sizing steady state load conditions

Steady state loading conditions

As like any other power source, UPS is a limited power supply and the capacity of the UPS is defined in KVA(apparent Power) and KW (real power).

To arrive at the capacity of UPS and the configuration of UPS, the following steps needs to be followed

• Step 1 Need of Load
• Step 2 Configuration of UPS
• Step 3 Check on the KVA & KW demand supplied by the UPS

Step 1: Need of Load

The load demand of the loads expected to be connected to the UPS.

(Note: The load power factor has to be measured at the site or can be assumed based on the past experience)

Step 2: Configuration of UPS

The criticality, of the loads will determine the necessary availability of the UPS. Based on the criticality the UPS capacity or configuration can be selected.

Where N is the number of UPS, required to support the Load. For critical load with 66% redundancy N>2, where a minimum of 2 UPS is required to support the load and 1 UPS for redundancy

Step 3: Selecting the required UPS capacity

Based on the total demand and the configuration of UPS, the capacity of UPS is selected. The total load in KVA and KW derived in step 1 will have to divided by N as selected in step 2 to arrive the UPS capacity.

Answer 3

When sizing UPS it is important to know the phase configuration required by both the mains supply and the loads, in addition to the overall load size. Electrical experts will often state both load size and phase configuration. An example would include ‘120KVA three phase’. This refers to a 120KVA load run from a three phase 415Vac, 50Hz supply. In terms of load sizing, this means that each phase (of the 3 phase electrical supply) will deliver upto 40KVA (or 174Amps at 230Vac). If the statement was 120KVA per phase then we would be looking at 3×120KVA per phase = 360KVA UPS load. The need for a 120KVA three phase UPS could be met with three single phase output 40KVA UPS provided the connected loads are single phase loads. These would be 3/1 configured and installed one per phase. However, the overall capital, installation and energy efficiency costs just rose by a factor of 3 compared to a single 120KVA UPS system installation. 3/1 UPS upto 60KVA are also used in office environment where the loads are single phase and this removes the need to balance the load connections in each of the three phases. Larger 3/1 UPS even upto 200KVA are typically required for DCS and SCADA loads in heavy industries like Power Plant, Steel Plant etc.

UPS Sizing steady state load conditions

Steady state loading conditions

As like any other power source, UPS is a limited power supply and the capacity of the UPS is defined in KVA(apparent Power) and KW (real power).

To arrive at the capacity of UPS and the configuration of UPS, the following steps needs to be followed

• Step 1 Need of Load
• Step 2 Configuration of UPS
• Step 3 Check on the KVA & KW demand supplied by the UPS

Step 1: Need of Load

The load demand of the loads expected to be connected to the UPS.

(Note: The load power factor has to be measured at the site or can be assumed based on the past experience)

Step 2: Configuration of UPS

The criticality, of the loads will determine the necessary availability of the UPS. Based on the criticality the UPS capacity or configuration can be selected.

Where N is the number of UPS, required to support the Load. For critical load with 66% redundancy N>2, where a minimum of 2 UPS is required to support the load and 1 UPS for redundancy

Step 3: Selecting the required UPS capacity

Based on the total demand and the configuration of UPS, the capacity of UPS is selected. The total load in KVA and KW derived in step 1 will have to divided by N as selected in step 2 to arrive the UPS capacity.

Answer 4

When sizing UPS it is important to know the phase configuration required by both the mains supply and the loads, in addition to the overall load size. Electrical experts will often state both load size and phase configuration. An example would include ‘120KVA three phase’. This refers to a 120KVA load run from a three phase 415Vac, 50Hz supply. In terms of load sizing, this means that each phase (of the 3 phase electrical supply) will deliver upto 40KVA (or 174Amps at 230Vac). If the statement was 120KVA per phase then we would be looking at 3×120KVA per phase = 360KVA UPS load. The need for a 120KVA three phase UPS could be met with three single phase output 40KVA UPS provided the connected loads are single phase loads. These would be 3/1 configured and installed one per phase. However, the overall capital, installation and energy efficiency costs just rose by a factor of 3 compared to a single 120KVA UPS system installation. 3/1 UPS upto 60KVA are also used in office environment where the loads are single phase and this removes the need to balance the load connections in each of the three phases. Larger 3/1 UPS even upto 200KVA are typically required for DCS and SCADA loads in heavy industries like Power Plant, Steel Plant etc.

UPS Sizing steady state load conditions

Steady state loading conditions

As like any other power source, UPS is a limited power supply and the capacity of the UPS is defined in KVA(apparent Power) and KW (real power).

To arrive at the capacity of UPS and the configuration of UPS, the following steps needs to be followed

• Step 1 Need of Load
• Step 2 Configuration of UPS
• Step 3 Check on the KVA & KW demand supplied by the UPS

Step 1: Need of Load

The load demand of the loads expected to be connected to the UPS.

(Note: The load power factor has to be measured at the site or can be assumed based on the past experience)

Step 2: Configuration of UPS

The criticality, of the loads will determine the necessary availability of the UPS. Based on the criticality the UPS capacity or configuration can be selected.

Where N is the number of UPS, required to support the Load. For critical load with 66% redundancy N>2, where a minimum of 2 UPS is required to support the load and 1 UPS for redundancy

Step 3: Selecting the required UPS capacity

Based on the total demand and the configuration of UPS, the capacity of UPS is selected. The total load in KVA and KW derived in step 1 will have to divided by N as selected in step 2 to arrive the UPS capacity.

Answer 5

When sizing UPS it is important to know the phase configuration required by both the mains supply and the loads, in addition to the overall load size. Electrical experts will often state both load size and phase configuration. An example would include ‘120KVA three phase’. This refers to a 120KVA load run from a three phase 415Vac, 50Hz supply. In terms of load sizing, this means that each phase (of the 3 phase electrical supply) will deliver upto 40KVA (or 174Amps at 230Vac). If the statement was 120KVA per phase then we would be looking at 3×120KVA per phase = 360KVA UPS load. The need for a 120KVA three phase UPS could be met with three single phase output 40KVA UPS provided the connected loads are single phase loads. These would be 3/1 configured and installed one per phase. However, the overall capital, installation and energy efficiency costs just rose by a factor of 3 compared to a single 120KVA UPS system installation. 3/1 UPS upto 60KVA are also used in office environment where the loads are single phase and this removes the need to balance the load connections in each of the three phases. Larger 3/1 UPS even upto 200KVA are typically required for DCS and SCADA loads in heavy industries like Power Plant, Steel Plant etc.

UPS Sizing steady state load conditions

Steady state loading conditions

As like any other power source, UPS is a limited power supply and the capacity of the UPS is defined in KVA(apparent Power) and KW (real power).

To arrive at the capacity of UPS and the configuration of UPS, the following steps needs to be followed

• Step 1 Need of Load
• Step 2 Configuration of UPS
• Step 3 Check on the KVA & KW demand supplied by the UPS

Step 1: Need of Load

The load demand of the loads expected to be connected to the UPS.

(Note: The load power factor has to be measured at the site or can be assumed based on the past experience)

Step 2: Configuration of UPS

The criticality, of the loads will determine the necessary availability of the UPS. Based on the criticality the UPS capacity or configuration can be selected.

Where N is the number of UPS, required to support the Load. For critical load with 66% redundancy N>2, where a minimum of 2 UPS is required to support the load and 1 UPS for redundancy

Step 3: Selecting the required UPS capacity

Based on the total demand and the configuration of UPS, the capacity of UPS is selected. The total load in KVA and KW derived in step 1 will have to divided by N as selected in step 2 to arrive the UPS capacity.