DE3006854C2 - Cooling system with monitoring arrangement for the transformer cooling of a power plant machine transformer - Google Patents

Description

65

The invention relates to a cooling system with a monitoring arrangement for transformer cooling of a power plant machine transformer with transformer core and transformer boiler, with the Cooling system two cooling circuits made up of a cooling oil supply branch, a cooling oil discharge branch, at least one pump and heat exchanger, the cooling oil supply branch and the cooling oil discharge branch to the Transformer boiler are connected and the two cooling circuits within the transformer boiler via common cooling oil inlet channels and cooling oil outlet channels are connected so that if the pump fails of one cooling circuit, the cooling oil quantity of the other is distributed over the entire transformer core, with further the pumps have a pump motor control with pump contactors and finally the monitoring arrangement Has thermocouples and oil flow detectors in the cooling circuits, which soft when the temperature is too high Cooling oil temperature a temperature monitoring signal or, if there is no flow, a flow monitoring signal produce.

In such a known cooling system (Siemens-Zeitschrift 32,1958, p. 463,464) are in the connecting pipelines, the bushings and in the öJraum to the relevant expansion vessels so-called Buchholz relays built-in Thermal monitors are used for the transformer Resistance and dial thermometers. There are oil level indicators and on the main expansion tank oil level indicator provided. To monitor that a fan is working properly, the Air flow an air flow detector. The oil circulation is controlled by oil flow sensors. Buchholz relay work with two floats, which are mounted in a housing and when they tilt, mercury contacts getting closed. In the event of a fault in the transformer, interruption, flashover. Leakage of the Transformer boilers create oil gas or air bubbles that are collected by the Buchholz relay and passed through Displacement of the oil from the housing bring one of the contact floats to tilt, so that a Warning device is triggered. In the event of strong gas development, the Buchholz relay is activated before the dormer rushes have reached the other swimmer actuated by the violent flow of oil. He works in general a shutdown of the transformer. Occasionally, single-float relays that are similarly effective are also used as Buchholz relays designated. The result of the known embodiment is an automatic shutdown realized in the event of excess temperature. However, not every overtemperature is so severe Fault that a shutdown of the transformer is necessary. - In practice it is switched off of an endangered transformer often not automatically, but rather by the operating personnel. This, too, is not free from disadvantages because the operator's discretion is involved and because of the reaction time of the operating personnel from the occurrence of a fault to action can be longer than it The urgency of the reported fault. In the context of the known measures, the Pump motor contactors in response cases explained below, but they only cause one Störmsldu.ig and contribute to an error message with transformer shutdown or to an automatic one Transformer shutdown nothing.

The invention is based on the object of a generic cooling system with a device provided, which links the monitoring signals and evaluates them in such a way that in the event of serious malfunctions a shutdown of the endangered transformer

takes place, but operation can be continued in the event of less serious malfunctions.

To solve this problem, the invention teaches that for the monitoring signal evaluation an electronic Signal linker with AND and OR logic is provided in which the temperature monitoring signals as well as the flow monitoring signals can be introduced, and that the signal linker when they occur of two UN D-linked temperature monitoring signals from the two cooling circuits or when they occur of two UN D-linked flow monitoring signals from the two cooling circuits as well as one with a flow monitoring signal if it occurs from the cooling circuit AND-linked temperature monitoring signal from the other cooling circuit is one Error message with transformer shutdown causes - A monitoring arrangement in a cooling system for transformers that work with two monitoring signals and signal linkers, namely on the one hand with a load current signal of the transformer and on the other hand with an oil temperature signal, is per se known (DD-PS 68 721). Both signals are in one Switching adds and brings over a power amplifier a relay to respond. The relay creates certain switching groups for the cooling devices switched on or off so that the cooling system operated according to the load condition of the transformer can be. A special combination logic is not implemented here. These known measures therefore have to solve the underlying of the invention Task contributed just as little as the fact that electronic signal linkers with AND and OR logic are used in other areas of technology, especially in computers are.

Within the scope of the invention, as (indirect) oil flow indicators, position indicators of any pump motor contactors of a pump motor control can be used, which respond to failure of the power supply, phase failure of the power supply, * o triggering of the pump motor overcurrent relay, failure of the control voltage and switching off the pump by hand. In the embodiment with a plurality of pumps and pump motor contactors in a refrigeration cycle, the invention teaches that the pump motor contactors of the individual cooling circuits are connected in series and in response of all Punpenmotorschützen in ek em cooling circuit, a monitoring signal is generated. This means that when a pump motor contactor responds, the corresponding contact closes' Ό

The invention is initially based on the knowledge that for solving the object of the invention Temperature monitoring may no longer take place on or in the transformer tank. It takes place in the Lines of the cooling circuits, separately for each cooling circuit.

The invention is based on the further knowledge that because of the coupling of the two cooling circuits in the Transformer boiler a transformer shutdown is only necessary if in both cooling circuits & o coinciding with a temperature monitoring signal. The invention works so far with the described AND operation of the temperature monitoring signals. An analogous, inventive consideration for the Cooling function monitoring leads to the result that only when two cooling function monitoring signals coincide it is necessary to switch off both cooling circuits. The transformer shutdown is also required according to the teaching of the invention if, as it were, diagonally in a cooling circuit The temperature monitoring signal receives an ICooling function monitoring signal in the other - and vice versa The cooling function monitoring is carried out in a simple and elegant way with flow measurement or monitoring the position of the pump motor contactors reliably released

In the following the invention is illustrated by means of a drawing which shows only one exemplary embodiment explained in more detail It shows in a schematic representation

F i g. 1 shows a cooling system according to the invention with cooling function monitoring through flow monitoring and

F i g. 2 the subject of F i g. 1 with cooling function monitoring by monitoring the position of the pump motor contactors.

In the figures one can initially see the cooling system with a monitoring arrangement for the transformer cooling of a power plant machine transformer with transformer not shown c. Core and transformer boiler 1. The cooling system has two cooling circuits 2, 3 comprising a cooling oil supply branch and a cooling oil discharge branch and in the embodiment of FIG. in each cooling circuit 2 or 3 two pumps 4 or 5 and two Wä; exchanger 6 or 7, in the exemplary embodiment the F i g. 2 each have a pump 4 or 5 and a heat exchanger 6 or 7. The heat exchangers 6, 7 are connected to the corresponding cooling water supply and discharge lines 8, 9. The cooling oil supply branch and the cooling oil discharge branch of each cooling circuit 2, 3 are connected to the transformer tank 1 connected. The two cooling circuits 2, 3 are inside the transformer tank 1 via common cooling oil inlet channels 10 and cooling oil outlet channels 11 connected, as indicated in the figures. One achieves in this way that in the event of failure of the pumps 4 or 5 of a cooling circuit 2 or 3, the amount of cooling oil of the other is on the entire transformer core distributed and the cooling maintained. The pumps 4, 5 have a Pump motor controls that are equipped with pump motor contactors 12, 13, which is only shown in FIG. 2 indicated became. In addition, the monitoring arrangement includes thermocouples 14, 15 which at zi; higher Cooling oil temperature a temperature monitoring signal 16a and 166, respectively.

For the monitoring, the arrangement is basically such that the thermocouples 14, 15 are arranged in the cooling circuits 2, 3. In addition, each cooling circuit 2, 3 is equipped with a cooling function monitoring device in the form of oil flow detectors 17, 18 which generate a flow monitoring signal i9a or 19Z> if the cooling function is missing. When two AND-linked temperature monitoring signals 16a, 16b are picked up from both cooling circuits 2, 3 or when two AND-linked flow rate monitoring signals 19a, 196 occur from both cooling circuits 2, 3, an error message with transformer shutdown occurs. An error message with transformer shutdown also occurs if a temperature monitoring signal 16 £> or 16a from the other cooling circuit is AND-linked with a rotary flow monitoring signal 19a or 196 from one cooling circuit.

In the embodiment according to FIG. 1, the cooling circuits 2, 3 have a flow monitoring device in the form of oil flow detectors 17 and 18. The

The flow monitoring device is used as a cooling function monitoring device used. If there is no flow, it generates a flow monitoring signal I9a. 196. For monitoring signal evaluation an electronic signal linker 20 with AND and OR logic is provided. In these electronic Signal linkers 20 are the temperature monitoring signals 16a, 166 and the flow monitoring signals 19a. 196 insertable. The circuit is made so that the electronic signal linker 20 m when two AND-linked temperature monitoring signals occur 16a, 166 from the two cooling circuits 2, 3 or if two AND-linked occur Flow monitoring signals 19a. 196 from the two cooling circuits 2, 3 an error message with r> Transformer shutdown causes, including the output line 21, 22 and 23, 24 to the electronic Signal linker 20 is connected. The transformer is also switched off if a with occurs a flow rate monitoring signal i9a or i96 from: - " one cooling circuit AND-linked temperature monitoring signal 166 or 16a from the other Cooling circuit.

In the embodiment according to FIG. 2, the pump motor control is equipped with pump motor contactors 12 -5 and 13, respectively. Here the design is initially made so that the pump motor contactors 12 or 13 respond to: failure of the power supply, phase failure of the power supply, triggering of the pump motor overcurrent protection relay, failure of the control voltage and switching off a pump by hand. Here, a position indicator is provided for each cooling circuit 2, 3 as a cooling function monitoring device is provided 17 and 18 for a Stellungsüberwachüng the "urnperimOiorschüize 12 and 13 respectively. These produce at one of i> enumerated above Ansprechfälle a position monitoring signal 16a, 166. For the Überwachungssignalauswcruing is again cjn electronic S: gna! linker 20 with AND and OR logic provided. Temperature monitoring signals 16a, 166 and position monitoring signals 19a, 196 can be introduced into this electronic signal linker 20. If two AND-linked temperature monitoring signals 16a, 166 from the two occur Cooling circuits 2, 3 or from two AND-linked position monitoring signals 196, 196 from the two cooling circuits 2, 3, in turn, an error message with transformer shutdown occurs via the outgoing lines 21, 22 or 23, 24. In this case, too, a transformer is switched off when a with a position monitoring signal 19a or 196 from the one cooling circuit AND-linked temperature monitoring signal 166 or 16a from the other cooling circuit.

It goes without saying that in the cooling systems according to the invention in each cooling circuit 2, 3 also several thermocouples 14 and 15, respectively, several oil flow detectors 17 and 18 and. with several Pumps 4 and 5 in each cooling circuit 2, 3 also have several pump motor contactors 12 and 13 and consequently position indicators 17 or 18 can be provided for monitoring the position of the pump motor contactors 12 and 13, respectively. then these different, signal-generating units are advantageously connected in series so that at Response of all thermocouples in one of the cooling circuits 2 or 3 a Tcrnpcraiuriibcrv / Achtingssigna! 16a, 166 is generated, furthermore in the absence of flow of all flow monitoring devices in one the cooling circuits 2 and 3, a flow monitoring signal 19a, 196 is generated, finally when all respond Pump motor contactors in one of the cooling circuits 2 or 3 a position monitoring signal 19a. 196 is generated and consequently the monitoring device can function in the manner described. In general i.iti the cooling circuits 2, 3 with several pumps 4, 5 equipped.

Within the scope of the invention there is the possibility of receiving signals from the monitoring arrangement Temperature monitoring signals 16a, 166, flow monitoring signals or steering monitoring signals 19a. 196 to be deducted, each reported individually or in special couplings to the control room where they are perceived and evaluated by the operating personnel. As part of the The invention is also the thermocouples 14, 15 of the temperature monitoring device for different Temperatures temperature monitoring signals 16a, 166 to decrease in accordance with the Cooling oil temperatures, if necessary, an automatic power reduction of the assigned transformer cause.

For this purpose 2 sheets of drawings

Claims (3)

Patent claims: 1. Cooling system with monitoring arrangement for the transformer cooling of a power plant machine transformer with transformer core and transformer tank, where the cooling system has two cooling circuits from the cooling supply branch, Has cooling oil discharge branch, at least one pump and heat exchanger, «o the cooling oil supply branch and the cooling oil discharge branch are connected to the transformer tank and the two cooling circuits within the transformer tank via common Cooling oil inlet channels and 'cooling oil outlet channels are connected so that in the event of a pump failure in one cooling circuit, the amount of cooling oil in the other affects the entire Transformer core distributed, 20th further wherein the pumps have a pump motor control with pumps protecting and wherein, finally, the monitoring arrangement in the cooling circuits thermocouples and oil flow detector has that at too high a cooling oil temperature, a & temperature monitoring signal or generate in the absence of flow, a Durchflußübcrwachungssignal, characterized in that for the monitoring signal evaluation an electronic Signalverknüpfer ( 20) is provided with AND and OR logic, in which the temperature monitoring signals (16a, i6b) and the flow monitoring signals (1? 3, 196 / can be inserted, and when two AND-linked temperature monitoring signals occur (16. * i6b) from the two cooling circuits (2, 3) or when two AND-linked flow monitoring signals occur (19a, 196 / from the two cooling circuits (2,3) and when one occurs with a flow monitoring signal (196 or 19a ; from the cooling circuit AND-linked temperature monitoring signal (16a or i6b) causes an error message with transformer shutdown from the other cooling circuit. 2. Cooling system according to claim 1, characterized in that position indicator as the oil flow indicator (17, 18) already existing pump motor contactors (12, 13) of a pump motor control are used that respond to failure of the power supply, phase failure of the power supply. Triggering of the pump motor overcurrent relay. Control voltage failure and switch-off the pump by hand. 3. Cooling system according to claim 2 in the embodiment with several pumps and pump motor contactors in a cooling circuit, characterized in that the pump motor contactors (12, 13) of the individual cooling circuits (2, 3) are connected in series and when all pump motor contactors respond (12, 13) a monitoring signal is generated in one of the cooling circuits (2, 3).