Ano ang resulta sa pag-ugnay sa paralelo sa tatlong phase transformers?

Ang mga Resulta sa Parallel Operation sa Tres-Phase Transformers

Ang parallel operation sa duha o mas dako pa nga tres-phase transformers usa ka common configuration sa power systems, gipangandoy sa pag-increase sa system capacity, reliability, ug flexibility. Apan, ang mga transformers kinahanglan molihok sa certain conditions aron siguraduhon ang safe, stable, ug efficient na parallel operation. Sumala ang mga resulta sa parallel operation sa tres-phase transformers ug related considerations.

1. Ang Conditions para sa Parallel Operation

Arong siguraduhon nga ang tres-phase transformers makalihok og safe sa parallel, ang sumusunod nga conditions kinahanglan matuman:

• Equal Rated Voltages: Ang rated voltages sa high-voltage ug low-voltage sides sa transformers kinahanglan identical. Kon ang voltages dili mag-match, mahimong moadto sa unbalanced currents o overloading.

• Same Turns Ratio: Ang turns ratio (ang ratio sa high-voltage side sa low-voltage side) sa transformers kinahanglan sama. Kon ang ratios dili sama, mahimong moadto sa inconsistent secondary voltages, causing circulating current, increased losses, ug reduced efficiency.

• Identical Connection Groups: Ang connection types (tulad sa Y/Δ, Δ/Y, etc.) sa tres-phase transformers kinahanglan sama. Ang different connection groups mahimong moadto sa phase differences, causing circulating currents o uneven power distribution.

• Similar Short-Circuit Impedance: Ang short-circuit impedance sa parallel-operating transformers kinahanglan as close as possible. Kon may significant difference sa short-circuit impedance, ang load distribution mahimong uneven, potentially causing one transformer moadto sa overloaded nindot ang uban underloaded.

• Same Frequency: Ang transformers kinahanglan molihok sa same frequency. Kini typically ensured sa pag-connect sa same power grid.

2. Ang Resulta sa Parallel Operation

a. Increased Capacity

Total Capacity: Kon multiple transformers molihok sa parallel, ang total system capacity mao ang sum sa individual transformer capacities. Tumong, duha 500 kVA transformers operating in parallel provide a total capacity of 1000 kVA. Kini allows the system to handle larger load demands.

b. Load Distribution

Ideal Load Distribution: Sa ideal scenario, kon tanang parallel-operating transformers meet the above conditions (especially having similar short-circuit impedance), ang load mahimong evenly distributed among the transformers. Each transformer will carry an equal share of the load current, ensuring stable system operation.

Non-Ideal Load Distribution: Kon ang short-circuit impedances sa transformers dili sama, ang load distribution mahimong uneven. Ang transformers with lower short-circuit impedance mahimong mogamit og more of the load, nindot ang uban with higher impedance mogamit og less. Kini uneven distribution mahimong moadto sa some transformers becoming overloaded, affecting system reliability and lifespan.

c. Circulating Currents

Generation of Circulating Currents: Kon ang parallel-operating transformers dili meet the above conditions (such as different turns ratios, connection groups, or short-circuit impedance), circulating currents may occur between the transformers. Circulating current refers to the flow of current between transformers in the absence of external loads. Circulating currents increase system losses and can cause transformers to overheat, reducing their lifespan.

Impact of Circulating Currents: The presence of circulating currents reduces the effective output capacity of the transformers because part of the current is used for internal circulation rather than supplying the load. Additionally, circulating currents can cause the transformers to heat up, increasing the risk of failure.

d. Improved Reliability

Redundancy: Parallel operation of transformers provides redundancy. Kon usa ka transformer fails or requires maintenance, ang uban mahimo mubuntag sa power, ensuring continuous system operation. Kini enhances the overall reliability and availability of the power system.

e. Cost Efficiency

Flexible Expansion: By operating in parallel, ang system's capacity mahimo moincrease incrementally without replacing existing transformers. Kini usa ka cost-effective solution for gradually expanding power systems.

Backup Capacity: Parallel-operating transformers mahimo mohatag og backup capacity. Sa normal conditions, tanang transformers nag-share sa load, apan kon usa ka transformer fails, ang uban mahimo mubuntag sa additional load, avoiding system interruption.

3. Considerations for Parallel Operation

a. Protective Devices

Differential Protection: Aron iprevent ang circulating currents o other abnormal conditions during parallel operation, differential protection devices are typically installed. Differential protection detects differences in current between the transformers and can quickly isolate a faulty transformer to protect the system.

b. Monitoring and Control

• Load Monitoring: Parallel-operating transformers should be equipped with load monitoring equipment to continuously track the load on each transformer, ensuring even load distribution. If uneven loading is detected, adjustments should be made promptly.

• Temperature Monitoring: Since parallel operation can lead to some transformers becoming overloaded, it is important to monitor the temperature of the transformers to prevent overheating and damage.

c. Maintenance and Inspection

• Regular Checks: Parallel-operating transformers should undergo regular inspections and maintenance to ensure optimal performance. Particular attention should be paid to checking the short-circuit impedance, connection groups, and other parameters to ensure they remain consistent for parallel operation.

• Fault Isolation: If one transformer fails, it should be immediately isolated from the system to avoid affecting the operation of the other transformers.

4. Summary

Parallel operation of tres-phase transformers mahimo moincrease significantly ang system capacity, reliability, ug flexibility, apan strict conditions kinahanglan matuman, such as equal rated voltages, turns ratios, connection groups, ug short-circuit impedance. Kon satisfied ang conditions, ang load mahimong evenly distributed among the transformers, ug ang system will operate stably. Apan, kon unsatisfied ang conditions, issues such as circulating currents ug uneven load distribution mahimong moadto, impacting system efficiency ug safety.

Parallel operation usab provides redundancy, allowing the system to continue operating even if one transformer fails, ug offers a cost-effective solution for gradual system expansion.