The method of calibration of DC current measurement equipment polarity in a kind of DC transmission system
Technical field
The present invention relates to the method for calibration of equipment in a kind of DC transmission system, particularly about the method for calibration of DC current measurement equipment polarity in a kind of DC transmission system.
Background technology
At present; converter valve two ends in HVDC (High Voltage Direct Current) transmission system, direct current utmost point bus bar side, DC bus bar side and AC line trackside have all been installed DC current measurement equipment, and its output is for DC power control, converter valve protection, DC bus protection, the protection of DC line and DC line protection etc.The direction of the DC current being obtained by DC current measurement device measuring is called polarity; if the direction of DC current measurement device measuring is identical with the direction of actual current in DC loop in DC transmission system; the polarity of DC current measurement equipment is correct; the control protective unit of all use DC current measurement equipment outputs all can normally be worked, otherwise will cause, controls the serious consequences such as function is undesired, protection action is incorrect.
It is the test that DC current measurement equipment and control protective unit must carry out after completing in installation, wiring that the polarity of DC current measurement equipment is carried out to verification.In the process of construction of existing high voltage direct current transmission project, mainly by single DC current measurement equipment being carried out to beam test and checking that whether the polarity of DC current of its output is correct, as Fig. 1, shown in Fig. 2, in prior art, the formation of DC transmission system at least comprises two AC system 1, four converter power transformers 2, four converter valve 3, four smoothing reactors 4 and some DC current measurement equipment 5, need to carry out respectively verification to each DC current measurement equipment 5 in DC transmission system, specifically comprise the following steps: 1. disconnect being connected of DC current measurement equipment 5 and other equipment.2. the DC current measurement equipment 5 disconnecting is connected with DC current signal generator 6.3. start DC current signal generator 6, the polarity of the DC current of DC current measurement equipment 5 outputs of series connection with it is carried out to verification.4. repeating step 1.~3., until the DC current measurement equipment 5 in DC transmission system is all completed to verification.Owing to there is a plurality of DC current measurement equipment in HVDC (High Voltage Direct Current) transmission system, available technology adopting is carried out respectively beam test method to each DC current measurement equipment will expend a large amount of human and material resources and time.
Summary of the invention
For the problems referred to above, the method of calibration that the object of this invention is to provide DC current measurement equipment polarity in a kind of DC transmission system of saving human and material resources and time, the method by primary side feeding current test can verification DC loop in the polarity of all DC current measurement equipment.
For achieving the above object, the present invention takes following technical scheme: the method for calibration of DC current measurement equipment polarity in a kind of DC transmission system, and it comprises the following steps: 1) DC transmission system that comprises AC system, converter power transformer, converter valve, smoothing reactor and some DC current measurement equipment is set; 2) disconnect DC current measurement equipment with in DC transmission system except direct current protecting device being connected of other equipment, and with wire, each DC current measurement equipment in same utmost point DC loop is connected; 3) DC current signal generator is connected in the loop of each DC current measurement equipment formation, forms closed loop current loop; 4) start DC current signal generator, and the DC current of DC current signal generator output is injected to closed loop current loop; 5), according to observation station records in the man-machine interface of DC current measurement equipment DC current and the Output rusults of direct current protecting device, judge that whether the polarity of DC current measurement equipment and DC current measurement equipment or its mode of connection be correct; 6) polarity of all DC current measurement equipment is completed after verification, the output of DC current signal generator is decreased to zero and close DC current signal generator; 7) remove the wire between each DC current measurement equipment and between DC current measurement equipment and DC current signal generator, recover the annexation of each equipment in former DC loop.
In described step 5), judge that whether the polarity of DC current measurement equipment and DC current measurement equipment or its mode of connection be correct, it specifically comprises the following steps: the output current of each DC current measurement equipment in (1) closed loop current loop all transfers in the man-machine interface with each DC current measurement equipment connection, and the output current that forms two above DC current measurement equipment of differential protection in the DC loop of DC transmission system all transfers in direct current protecting device; (2) judge that whether the direction of the DC current observing in the man-machine interface of DC current measurement equipment is identical with the direction of actual current in DC loop in DC transmission system; If the direction of the DC current observing is identical with the direction of actual current in DC loop in DC transmission system, illustrate that the polarity of DC current measurement equipment is correct, execution step (3) in the man-machine interface of each DC current measurement equipment; If the direction of the DC current observing in the man-machine interface of each DC current measurement equipment is not identical with the direction of actual current in DC loop in DC transmission system, the polarity that DC current measurement equipment is described is incorrect, corrigendum DC current measurement equipment or its mode of connection, again the polarity of the DC current measurement equipment after corrigendum is carried out to verification, until the whole correct rear execution steps of the polarity of each DC current measurement equipment (3); (3), according to the Output rusults of direct current protecting device, judge that whether DC current measurement equipment or its mode of connection be correct; If direct current protecting device output 0, judges that DC current measurement equipment or its mode of connection are correct, complete the verification to all DC current measurement equipment polarity, close DC current signal generator; If direct current protecting device output 1; the mode of connection of DC current measurement equipment is incorrect; after the mode of connection of corrigendum DC current measurement equipment, again the polarity of the DC current measurement equipment after corrigendum is carried out to verification; until each DC current measurement equipment or its mode of connection all correct after; complete the verification to all DC current measurement equipment polarity, close DC current signal generator.
In described step 4), the output current value of controlling DC current signal generator is greater than the minimum current value of each DC current measurement recognition of devices.
In described step 5), direct current protecting device comprises subtracter and comparer, and the DC current of two above DC current measurement equipment transfers to subtracter and calculates, and result of calculation and default reference value compare, if result of calculation is less than reference value, comparer output 0; Otherwise, comparer output 1.
The present invention is owing to taking above technical scheme, it has the following advantages: 1, the present invention is owing to DC current signal generator being connected in the loop of each DC current measurement equipment formation, and the DC current of DC current signal generator output is injected to closed loop current loop, whether the polarity that judges DC current measurement equipment by the DC current that in the man-machine interface at DC current measurement equipment, observation station records is correct, therefore the present invention tests the polarity that gets final product all DC current measurement equipment in verification DC loop by primary side feeding current, thereby save a large amount of manpowers, material resources and time.2, the present invention due in closed loop current loop by a direct current protective device and more than two DC current measurement devices in series; further by observe the differential amount of more than two DC current of DC current measurement equipment output on direct current protecting device; whether the polarity that judges DC current measurement equipment is correct, so the present invention can improve the accuracy of DC current measurement equipment polarity verification.
Accompanying drawing explanation
Fig. 1 is the structural representation of DC transmission system
Fig. 2 is the equipment connecting relation schematic diagram while adopting existing method respectively single DC current measurement equipment to be carried out to beam test
Fig. 3 is process flow diagram of the present invention
Fig. 4 is the equipment connecting relation schematic diagram while adopting method of calibration of the present invention to carry out verification to the polarity of DC current measurement equipment
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in detail.
In DC transmission system of the present invention, the method for calibration of DC current measurement equipment polarity realizes based on DC transmission system, as shown in Figure 1, DC transmission system comprises two AC system 1, four converter power transformers 2, four converter valve 3, four smoothing reactors 4 and some DC current measurement equipment 5.Wherein, two AC system 1 connect converter valve 3 by converter power transformer 2 respectively, and converter valve 3 is connected with DC current measurement equipment 5 with smoothing reactor 4 respectively; Two groups of DC loop that consist of two converter valve 3 and some DC current measurement equipment 5 are respectively the utmost point one DC line and the utmost point two DC line.
As shown in Figure 3, in DC transmission system of the present invention, the method for calibration of DC current measurement equipment polarity comprises the following steps:
1) DC transmission system that comprises AC system 1, converter power transformer 2, converter valve 3, smoothing reactor 4 and some DC current measurement equipment 5 is set.
2) as shown in Figure 4, disconnect being connected of other equipment such as DC current measurement equipment 5 and converter valve 3, smoothing reactor 4, and with wire, each DC current measurement equipment 5 in same utmost point DC loop is connected.If by connections such as pipe mother or wires, keep the connection between each DC current measurement equipment 5 between each DC current measurement equipment 5.
3) as shown in Figure 4, DC current signal generator 6 is connected in the loop of each DC current measurement equipment 5 formations, forms closed loop current loop.
4) start DC current signal generator 6 and make it output current, the output current value of DC current signal generator 6 is greater than the discernible minimum current value of each DC current measurement equipment 5.
5) the basis DC current that observation station records in the man-machine interface of DC current measurement equipment 5 and the Output rusults of direct current protecting device 7, judge that whether the polarity of DC current measurement equipment 5 is correct, and it specifically comprises the following steps:
(1) output current of each DC current measurement equipment 5 in closed loop current loop all transfers in the man-machine interface (not shown) being connected with each DC current measurement equipment 5, and the output current that forms two above DC current measurement equipment 5 of differential protection in the DC loop of DC transmission system all transfers in direct current protecting device 7.
(2) judge that whether the direction of the DC current observing in the man-machine interface of DC current measurement equipment 5 is identical with the direction of actual current in DC loop in DC transmission system;
If the direction of the DC current observing in the man-machine interface of each DC current measurement equipment 5 is identical with the direction of actual current in DC loop in DC transmission system in DC loop in DC transmission system, the polarity that DC current measurement equipment 5 is described is correct, execution step (3);
If the direction of the DC current observing in the man-machine interface of each DC current measurement equipment 5 is not identical with the direction of actual current in DC loop in DC transmission system, the polarity that DC current measurement equipment 5 is described is incorrect, corrigendum DC current measurement equipment 5 or its mode of connection, execution step 2)~5), until the whole correct rear execution steps of the polarity of each DC current measurement equipment 5 (3).
(3) according to the Output rusults of direct current protecting device 7 outputs, judge that whether DC current measurement equipment 5 or its mode of connection be correct;
If 7 outputs 0 of direct current protecting device, judge that DC current measurement equipment 5 or its mode of connection are correct, execution step 6);
If direct current protecting device 7 outputs 1; the mode of connection of DC current measurement equipment 5 is incorrect; repeating step 2 after the mode of connection of corrigendum DC current measurement equipment 5)~5), until each DC current measurement equipment 5 or its mode of connection are all correctly rear, perform step 6).
6), after the polarity verification of all DC current measurement equipment 5 completes, the output of DC current signal generator 6 is decreased to zero and close DC current signal generator 6.
7) remove the wire between each DC current measurement equipment 5 and between DC current measurement equipment 5 and DC current signal generator 6, recover the annexation of each equipment in former DC loop.
Above-mentioned steps 5) in, direct current protecting device 7 comprises subtracter 71 and comparer 72, the DC current of two above DC current measurement equipment 5 transfers to and in subtracter 71, calculates the differential amount of DC current, and the differential amount of the DC current calculating and default reference value are compared, if the differential amount of DC current is less than reference value, comparer 72 outputs 0; Otherwise, comparer 72 outputs 1.
The various embodiments described above are only for illustrating the present invention; wherein the structure of each parts, connected mode and method step etc. all can change to some extent; every equivalents of carrying out on the basis of technical solution of the present invention and improvement, all should not get rid of outside protection scope of the present invention.