A kind of large-size thermal power plant emergency bearing oil pump electric supply installation
Technical field
The utility model belongs to power supply, control field, is specifically related to a kind of large-size thermal power plant emergency bearing oil pump electric supply installation.
Background technology
In the power supply design of large-size thermal power plant emergency load, be generally connected on security personnel's section upper, security personnel's section is normally powered by thermal power generation unit, when accident, is powered by diesel engine generator.And diesel engine generator because of various reasons, starts slow or can not start sometimes, cannot provide as early as possible AC power.Cause critical security personnel's load of thermal power generation unit in seeking time, to start wanting, cause the unit damage or damage of running up.
Therefore, how to increase power supply reliability, reduce operating cost, for ensureing that power plant's production safety operation has very great meaning.
Utility model content
The purpose of this utility model is to overcome the shortcoming existing in above-mentioned prior art, and a kind of large-size thermal power plant emergency bearing oil pump electric supply installation is provided, and has stability high, the advantage that operating cost is low.
For achieving the above object, the utility model by the following technical solutions: comprise the alternating current circuit and the DC line that are all connected to frequency converter input, inverter output terminal connects load;
Described alternating current circuit comprises: the interchange inlet wire that connects security personnel's PC cabinet is connected to frequency converter input through the first protective device breaker of plastic casing and the first contactor of being arranged in the A.C. contactor group of interlocking;
Described DC line comprises: the charger or the batteries that are connected to frequency converter input; Or the direct current inlet wire that connects emergency bearing oil pump becomes and the second contactor of being arranged in the A.C. contactor group of interlocking is connected to frequency converter input through the second protective device breaker of plastic casing, check diode, inverter, isolation;
On described frequency converter, be also provided with DCS command input interface.
Between described frequency converter and load, be provided with service entrance switch.
Described frequency converter is voltage-source type low voltage frequency converter.
Described bearing power is less than 200kW.
Described load is for exchanging oil pump, and the input voltage of oil pump is 380V.
The input voltage of described alternating current circuit is 380V, frequency 50Hz.
The input voltage of described DC loop is 220V.
The utlity model has following beneficial effect: the prior art of comparing, the utility model is by arranging the direct-flow input circuit in parallel with ac input circuit, and ac input circuit and direct-flow input circuit are all connected in frequency converter, owing to having increased direct-flow input circuit, thereby make the device can be in the situation that emergency power supply loses, adopt DC inversion that power supply is provided.Due in start-up course owing to having adopted frequency converter, starting current is lower than the direct starting current of motor, be conducive to reduce the capacity of inverter, the capacity of direct current system, avoid, because starting problem strengthens direct current system capacity and capacity of short circuit, having reduced the investment of whole direct current system and the utility model device; Harmonic wave in the electric motor starting stage is less, meets the requirement of the quality of power supply, and motor and electrical network are not impacted.Thereby the stability that has improved device, has reduced operating cost.
Brief description of the drawings
Fig. 1 is the utility model schematic diagram;
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in further detail.
Referring to Fig. 1, the utility model comprises the alternating current circuit and the DC line that all connect frequency converter 7 inputs, is also provided with DCS command input interface on frequency converter 7, and frequency converter 7 outputs connect load 8, between frequency converter 7 and load 8, are provided with switch 9.Alternating current circuit comprises: the interchange inlet wire 1 that connects security personnel's PC cabinet is connected to frequency converter 7 inputs through the first protective device breaker of plastic casing GS003 and the first contactor GS002 of being arranged in the A.C. contactor group 6 of interlocking; DC line comprises: the charger or the batteries that are connected to frequency converter 7 inputs; Or connect emergency bearing oil pump direct current inlet wire 2 through the second protective device breaker of plastic casing GS005, check diode, inverter 4, isolation become 5 and the second contactor GS004 of being arranged in the A.C. contactor group 6 of interlocking be connected to frequency converter 7 inputs; Frequency converter 7 is voltage-source type low voltage frequency converter.Load 8 is for exchanging oil pump, and the input voltage of interchange oil pump is 380V.The input voltage of alternating current circuit is 380V, frequency 50Hz.The input voltage of DC loop is 220V.
The important load of the pumps in thermal power plant is grease pump, jacking oil pump, fire pump, and this product is also suitable for important fan-type load.
The utility model can preferentially utilize the intrinsic direct current system in thermal power plant to power to load.When away from DC power supply, the utility model can carry charger and batteries, realizes DC power supply for subsequent use.
Using method of the present utility model is as follows:
For the interchange emergency bearing oil pump of normal operation; normally powered by AC system; the contactor being connected with the first protective device breaker of plastic casing GS003 is connected; through inverter supply oil-feed pump; DC loop the second protective device breaker of plastic casing GS005 connects, once exchange dead electricity, system automatically switches to DC power supply; be less than 3s switching time, ensure the stable of oil pump systems oil pressure.Recover if exchanged, system automatically or a distant place be manually switched to ac power supply.
For exchanging emergency bearing oil pump, normally AC and DC power supply is all connected, the first contactor GS002 closes a floodgate, and the second contactor GS004 disconnects.In the time that frequency converter 7 obtains DCS order, for oil-feed pump power supply, pump start work.When AC power loses, the first contactor GS002 tripping operation, interlocking the second contactor GS004 closes a floodgate, and is switched to DC power supply, pump start work.Recover when AC power, system automatically switches to Alternating Current Power Supply.
Above content is the further description of the utility model scheme being done in conjunction with concrete preferred implementation; the embodiment that can not assert the utility model scheme only limits to this; for the utility model scheme person of an ordinary skill in the technical field; do not departing under the prerequisite of the utility model plan plot; can also make some simple deduction or replace, all should be considered as belonging to the utility model and determine scope of patent protection by submitted to claims.