What are The Protection Advantages of Silent Diesel Generator Sets

Silent genset can reduce noise and are very popular in residences, hospitals and other places. In recent years, the market for silent diesel generators has become more and more demanding. Let's take a look at the silent diesel generators below. Ten protection advantages.

1. Silent diesel generator loss-of-excitation protection.

The loss-of-excitation protection is used as a loss-of-excitation fault protection when the excitation current of the generator drops abnormally or disappears completely. It is composed of criteria such as excitation low voltage Ufd(P), system low voltage, static stability impedance, TV disconnection whose setting value changes automatically with active power, which act on signalling and de-excitation respectively. Both the excitation low voltage Ufd(P) criterion and the static stability impedance criterion are related to the static stability boundary, which can detect whether the generator loses its static stability due to loss of excitation. The static stability impedance criterion acts at the static stability boundary after the loss of magnetism.

2. Mute diesel generator overexcitation protection.

Overexcitation protection is a protection that reflects the excessive working magnetic density of the iron core caused by the generator's frequency reduction or excessive voltage. The overexcitation protection is divided into high and low settings. The low setting sends a signal after a fixed delay of 5s and reduces the excitation voltage (the function of reducing the excitation voltage and excitation current is temporarily unused), and the high setting operates in de-loading after the inverse time limit. Demagnetization. The upper limit of the inverse time delay is 5 seconds, and the lower limit is 200 seconds.

3. Silent diesel generator stator grounding protection.

Generator stator grounding protection is used as a generator stator single-phase grounding fault protection. It consists of two parts: the fundamental zero sequence voltage part and the third harmonic voltage. The fundamental zero sequence voltage protects the single-phase stator winding in the 95% area from the machine end to the machine tail. The grounding fault is composed of reflecting the principle of zero-sequence voltage at the generator end, which acts on the demagnetization after a time limit of t1 (3s); the third harmonic voltage protects the single-phase grounding fault of the stator winding from the generator tail to 30% of the generator end. The neutral point of the generator and the third-harmonic principle at the generator end are formed, and act on the signal after a time limit of t2 (5s). The two constitute 100% stator grounding protection. The protection is equipped with a PT disconnection lock.

4. Silent diesel generator stator turn protection.

The protection is composed of the longitudinal zero sequence voltage and the negative sequence direction criterion of the fault component. PT disconnection blocking measures are set up as the main protection for the generator's internal turn and phase short circuit and the open welding of the stator winding. The negative sequence direction criterion of the fault component is passed Detecting the negative-sequence power flowing out of the generator to realize the longitudinal zero-sequence voltage criterion is realized by detecting the longitudinal 3UO output by the 3PT open delta winding whose neutral point is directly connected to the neutral point of the generator but not grounded. The protection action is at full stop.

5. Silent diesel generator out-of-step protection.

The protection uses a three-impedance element to detect the number of sliding poles and determine the location of the oscillation center through the change of the impedance trajectory. In the case of short-circuit fault, system oscillation, voltage circuit disconnection, etc., the protection will not malfunction. The protection generally acts on the signal; when the oscillation center is inside the generator-transformer group, the protection stage I starts and sends a trip command via t1 (0.5s), which acts on de-excitation; when the oscillation center is outside the generator-transformer group, the protection The start of section II is signaled at t2(2s). The protection device is equipped with a current blocking device to ensure that the current does not exceed the rated out-of-step breaking current of the circuit breaker when the circuit breaker is off.

6. Low-frequency cumulative protection for silent diesel generators.

The low-frequency accumulation protection reacts to the cumulative effect of the reduced frequency of the system on the steam turbine. The protection consists of a sensitive frequency relay and counter, and is blocked by the auxiliary contact of the outlet circuit breaker (that is, the low-frequency accumulation protection also exits when the generator exits operation), and the cumulative system frequency is low When the frequency is set at 47.5 Hz, when the accumulated time reaches the set value of 3000 seconds, the signal will be sent after a delay of 30 seconds. The device can be monitored in real time during operation: fixed value, frequency f and cumulative time display.

7. Silent diesel generator excitation circuit overload protection.

Excitation circuit overload protection is used to protect the rotor excitation circuit from overcurrent or overload. It is connected into a three-phase type and consists of two parts: definite time and inverse time limit. The operating current of the definite time part is set according to the condition that it can be reliably returned under the maximum rated current of normal operation. After the time limit t1 (5s), it acts on the signal and reduces the excitation current (the function of reducing the excitation current is not used); the action characteristic of the inverse time part is according to the generator The overload capacity of the excitation winding is determined, and the protection action is in de-energization and de-excitation. The upper limit of the inverse time limit is 10 seconds.

8. One-point grounding protection for the rotor of silent diesel generator.

The generator rotor one-point grounding protection is used to reflect the one-point ground fault of thegenerator rotor circuit. The protection adopts the ping-pong switching principle. The positive and negative ground voltages of the rotor circuit are sampled in turn, and the rotor grounding resistance is calculated in real time by solving two different ground loop equations. And grounding position. The protection will act on the signal after a delay of 2 seconds.

9. Symmetrical overload protection for silent diesel generators.

The protection device is composed of two parts: definite time and inverse time limit. The definite time part acts on the signal after the time limit of 5 seconds. The inverse time action characteristic is determined according to the generator's ability to withstand the overload current, and the action is in de-loading. The protection device can reflect the heat accumulation process of the generator stator.

10. Negative sequence overload protection for silent diesel generators.

The protection device is composed of two parts: definite time and inverse time limit. The definite time limit action current is set according to the long-term allowable negative sequence current value of the generator and the current value that avoids the imbalance of the negative sequence current filter under the maximum load. The second acts on the signal. The inverse time action characteristic is determined according to the ability of the generator to withstand negative sequence current, and the action is in de-excitation and de-excitation.

If you want to know more about diesel generators, welcome to contact by email dingbo@dieselgeneratortech.com.