Parallel operation of generators

Yes.

Guru,

How is this made possible,i mean shutting of breakers in the panel from the panel?

To give a aux.contact at field and hard wire to the panel breaker?

A shunt-trip circuit breaker can be made to open (break) by the presence vs. absence of a control signal.

A motorized circuit breaker can be opened and closed by a circuit that operates the motor each way.

A current sensor with a relay can be used to operate either of these two schemes. (Closing the breaker for a second generator is more complicated, because it requires synchronization.)

Several variations are possible according to desired plan and cost.

See this link

Yes, and you must have the load shedding scheme in this case for the system stability. The load shedding scheme ensures the availability of electrical power to all essential and most critical loads. This is achieved by switching off nonessential loads in case of a shortage of power in the electrical system due to loss of generation capacity. In this case, every major load should have a load shedding selector switch based on the criticality of the load (generally loads are categorized in 3 or 4 groups and so 3 or 4 position selection switch is used). This selector switch of a particular load determines if the load will be tripped in case of the low generating capacity. If there is low generating capacity in the system, the load shedding scheme sends trip signals to the loads and the low priority (non-critical) loads trip according their selections.

There are couple of ways the load shedding scheme determines the available capacity, the most common systems are:

- System frequency monitoring

- Breaker interlock system

System frequency monitoring: In this system the load shedding scheme monitor the system frequency. With lower generating capacity the system frequency drops and based on the lower system frequency, the load shedding scheme determines and sends signal to the loads.

Breaker interlock system: In this system a logic circuit is prepares using the auxiliary contacts of the generators and coupler (tie-breaker) so that the availability of number of generators is identified. Based on this logic, the load shedding scheme sends signal to the loads.

See this link:

http://www.mmpss.com/docs/etap/ILS_Fast_Optimal.pdf

- MS