Options in order to influence the output in the electrical power area

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Directly switchable devices

Devices which can be switched off briefly without interrupting any production processes are part of this group (industrial furnaces, pumps for water storages etc.).

The loads have a fixed value. In general the are depended on the device and therefore known of measureable.

Direct heatings

Because of their storage effect, these device can be switched off briefly without decreasing the quality of supply significantly (heating in warm water storages, electrically operated floor heatings etc.).

The loads consist of a consistent part and a part which is temperature-dependent. Additional the load is dependent on how long the device was switched off.

Monovalent heat pumps

In general these pumps are operated in the same way as direct heatings.

The temperature-dependent part is more distinctive and rise with falling outside temperatures (pumps used for generating heat including air conditioners) or rises with rising outside temperatures (air conditioners). The load is dependent on how long the device was switched off.

Bivalent heat pumps

These can choose between fuels they use. Beneath a certain temperature they are switched to a different fuel by their control unit of by the optimization.

At that no supply constraints emerge for the devices. These components are only switched in the long term and restrictively because the switching should not take place constantly.

When the temperature falls, the load increases up to the switching point. There it vanishes completely.

Night storage heatings

These devices are supplied with energy according to schedule or if there is any needed output during low rate periods. They are switched off during the remaining time.

The load depends essentially on the outside temperature. It is noticeable how many heatings are switched on (this is limited by the installed power) and how long they are charged.

Peak load aggregates and emergency power aggregates

These aggregates are switched on/off as required. In some cases these aggregates are controllable. The number of uses should be limited because the start of these aggregates coupled with additional costs on wear. In addition these aggregates should run for a minimum time in order to avoid thermal damages.

Combined heat and power units (CHPs)

These aggregates were primarily built to generate heat and are controlled by the heat demand during their operation (heat priority).

Some aggregates can be directly used to generate electric power (electric power demand). In general this operational mode is inefficient if the generated heat is not used at the same time. Therefore the use is only beneficial if the heat demand is corresponding or there is a possibility to store the heat.

The load reduction with regard to the take over point depends on the nominal size and for controlled or heat demand controlled aggregates from their working point.

It is quiet common to combine aggregates to groups. According to the heat demand, a certain quantity from the group is used. The maximum power lowering in the electrical power area is given by the number an nominal power of the used aggregates.

Lowering the voltage

In the electrical power area it is possible to lower the voltage in some grids. In order to achieve this, the transformers to the medium voltage level are switched to a lower level.

The voltage-dependence of the devices (ohmic load) causes another load demand provided that the voltage or output is not adjusted by subordinated controls.

The load reduction is dependent on the grid load, on the possible lowering of the voltage (minimum voltages must be adhered to) and on the composition of the devices.