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Home » Application » Page 2
This application introduced Gozuk inverter Power Plant, made comparison for energy saving, explained application prospect of variable frequency drive.
Energy saving effect
1) inverter parameter
2) motor parameter
3) Calculation
For fan and pump: Q∝n ,H∝n2,P∝n3
n---speed;
Q---flow;
H---pressure;
P—shaft power
When motor speed decreases to 80% of rated speed, input power of system (inverter + motor) decreases to 51% of that in rated speed. Thus, energy saving effect is more obvious when speed is low.
Make comparison in same working conditions:
The reconstruction cost can be recovered within 18 months.
Energy saving effect
1) inverter parameter
Model |
Gozuk Inverter |
Input vlotage | 6kV |
Rated current | 130A | Rated power | 1000kW |
2) motor parameter
Rated power | 1000kW | Rated voltage | 6kV |
Rated speed | 990rpn | Rated current | 118.8A |
3) Calculation
For fan and pump: Q∝n ,H∝n2,P∝n3
n---speed;
Q---flow;
H---pressure;
P—shaft power
When motor speed decreases to 80% of rated speed, input power of system (inverter + motor) decreases to 51% of that in rated speed. Thus, energy saving effect is more obvious when speed is low.
Make comparison in same working conditions:
Load | inverter before | inverter after | Energy saving rate |
125MW | 70A | 48A | 25% |
100MW | 55A | 29A | 40% |
The reconstruction cost can be recovered within 18 months.
Frequency control is widely used in several fields for its superiority
in energy-saving, adjustment precision, adjustment range and easy to
communicate with automatic control system. This text is aiming to
illustrate its broad prospects by introducing and concluding several
success cases.
1. Frequency control of boiler's fan
1.1 Application of the boiler's SA fan
The boiler is circulation boiler which is equipped with ID fan, PA fan, SA fan. The parameters as below:
As is known in boiler's regular service, there are considerable variety in fuel composition, heat load, power load, and seasons. Thus, the air for the boiler varies greatly. However, the fan of boiler is designed according to the maximum air flow in full load. In the mean time, there is certain redundancy for air flow in case of boiler's accident. Generally the power of fan is large. From the statistic, average opening of the wind shield in normal condition, 48% in ID fan, 45% in SA fan. Adjusting shield causes a large quantity of energy waste on overcoming the shield resistance. Plant efficiency is low.
At the end of 2000, we planned to choose SA fan of #1 to reform. Considering the fan redundancy, we purposely chose inverter of 132kW to control the fan of 160kw. The inverter started to run in January 2001. By a long term running, the current of the fan reduces from 135A to 75A, which reaches obvious energy saving and meets the requirement of boiler operation. According to the ammeter, energy saving rate is 45% and the cost is recovered in one year. Furthermore, the motor is improved in thermo of start-up, adjustment, controlling and operation. For the perfect benefit, we reform the fans in the other unit later. In design of bypass circuit, we choose double-throw switch in manual as its low-cost, good performance, easy to connect and install and high reliability. The circuit is below:
1. Frequency control of boiler's fan
1.1 Application of the boiler's SA fan
The boiler is circulation boiler which is equipped with ID fan, PA fan, SA fan. The parameters as below:
- ID fan: Y400-6, 400kW, 6kV, 47.3A
- PA fan: Y355-4, 250kW, 6kV, 29.3A
-
SA fan: Y315L1-4, 160kW, 380V, 289A
Average current |
Average opening |
Maximum opening |
Maximum current |
Minimum current |
PA Fan |
||||
21 A |
50% |
55% |
23 A |
20 A |
ID Fan |
||||
25 A |
48% |
50% |
28 A |
24 A |
SA Fan |
||||
135 A |
45% |
50% |
140 A |
130 A |
As is known in boiler's regular service, there are considerable variety in fuel composition, heat load, power load, and seasons. Thus, the air for the boiler varies greatly. However, the fan of boiler is designed according to the maximum air flow in full load. In the mean time, there is certain redundancy for air flow in case of boiler's accident. Generally the power of fan is large. From the statistic, average opening of the wind shield in normal condition, 48% in ID fan, 45% in SA fan. Adjusting shield causes a large quantity of energy waste on overcoming the shield resistance. Plant efficiency is low.
At the end of 2000, we planned to choose SA fan of #1 to reform. Considering the fan redundancy, we purposely chose inverter of 132kW to control the fan of 160kw. The inverter started to run in January 2001. By a long term running, the current of the fan reduces from 135A to 75A, which reaches obvious energy saving and meets the requirement of boiler operation. According to the ammeter, energy saving rate is 45% and the cost is recovered in one year. Furthermore, the motor is improved in thermo of start-up, adjustment, controlling and operation. For the perfect benefit, we reform the fans in the other unit later. In design of bypass circuit, we choose double-throw switch in manual as its low-cost, good performance, easy to connect and install and high reliability. The circuit is below:
Tags: inverter, Power Plant