阅读说明：本技术 一种发电机组ct间接二次通流方法 (CT indirect secondary through-flow method for generator set ) 是由 张宇峰 马晨原 翟鹏 寇林 杨志龙 于 2020-07-10 设计创作，主要内容包括：一种发电机组CT间接二次通流方法,包括以下步骤：1)进行机组CT二次回路通流试验前的准备检查工作,待所有前期工作准备完成后打开继电保护测试仪装置装置电源,调节其输出额定电流值的百分之五十,记录采集该组CT二次回路连接的所有设备电流值,检查各设备二次电流显示值及测量值与继电保护测试仪所加额定电流百分之五十值误差是否在准许范围内,调节继电保护测试仪使其输出值达到额定,记录采集该组CT二次回路的所有设备电流值,判断所测的CT二次额定电流值与所加CT二次额定电流值误差是否在准许范围内,CT二次通流实验结束。本发明节省了时间、人力、同时避免了试验人员长期暴露在复杂现场环境的情况,提高了工作安全。(A CT indirect secondary through-flow method of a generator set comprises the following steps: 1) the method comprises the steps of carrying out preparation checking work before a unit CT secondary circuit through-flow test, turning on a power supply of a relay protection tester device after all early work preparation is finished, adjusting fifty percent of an output rated current value of the relay protection tester device, recording and collecting current values of all devices connected with the unit CT secondary circuit, checking whether errors between display values and measured values of the secondary current of all the devices and fifty percent of the applied rated current of the relay protection tester are within an allowable range, adjusting the relay protection tester device to enable the output value of the relay protection tester device to reach a rated value, recording and collecting current values of all the devices of the unit CT secondary circuit, judging whether errors between the measured CT secondary rated current value and the applied CT secondary rated current value are within the allowable range, and finishing a CT secondary through-flow test. The invention saves time and labor, avoids the condition that the testing personnel are exposed in a complex field environment for a long time, and improves the working safety.)

1. A CT indirect secondary through-flow method of a generator set is characterized by comprising the following steps:

1) carrying out preparation checking work before a unit CT secondary loop through-flow test, and entering the step 2 after all previous work preparation is finished);

2) turning on a power supply of a relay protection tester device of the relay protection tester, adjusting fifty percent of the output rated current value of the relay protection tester device, and entering step 3);

3) recording and collecting current values of all devices connected with the group of CT secondary circuits, and then entering the step 4);

4) checking whether errors between the secondary current display values and the measured values of the equipment and fifty percent of rated current applied by the relay protection tester are within an allowable range, and determining current display error values of the equipment by an equipment specification generally, if no special description exists, the error values are not more than +/-5%, if yes, entering a step 5), otherwise, entering a step 6);

5) adjusting the relay protection tester to enable the output value of the relay protection tester to reach a rated value, and entering step 7);

6) closing the relay protection tester, checking the group of CT secondary circuits and connected equipment, and entering the step 2 after fault removal;

7) recording and acquiring current values of all devices of the set of CT secondary circuits, and then entering step 8);

8) judging whether the error between the measured CT secondary rated current value and the added CT secondary rated current value is in an allowable range, and generally, determining the error value of current display of each device by a device specification, if no special description exists, the error value of the current display should not exceed +/-5%, if yes, entering step 10), otherwise, entering step 9);

9) closing the relay protection tester, checking a secondary circuit and equipment, and entering a step 5 after defects are eliminated);

10) and finishing the CT secondary through-flow experiment.

2. The indirect secondary through-flow method for the CT of the generator set according to claim 1, wherein the preparation and inspection work before the indirect CT secondary through-flow test in the step 1) is specifically carried out as follows:

101) checking the integrity and correctness of the secondary loops corresponding to all the CTs in the group, wherein the integrity and correctness comprise whether the connection position of a cable and equipment is accurate, whether the connection at the interface of the secondary cable is firm and reliable, whether a terminal sliding sheet can be connected at the equipment is completely connected, and no looseness exists;

102) selecting any electric equipment connected with a set of CT secondary circuits as a dosing starting end of the relay protection tester, disconnecting the connection between the equipment and a connectable terminal of the set of CT secondary circuits (so that a dosing device needs to independently flow through a channel of the equipment after a test is finished to ensure that the sampling function of an equipment body is correct), then connecting a power supply of the relay protection tester, connecting the output end of the relay protection tester with a CT current return path side of a disconnection point of a current circuit of the electric equipment, preparing a set of short connecting wires in a CT outlet terminal box, connecting one side of the short connecting wires with the CT circuit dosed by the relay protection tester, and connecting the short connecting wires to the corresponding CT current outlet circuit when the CT secondary circuit of which equipment needs to flow through;

103) and disconnecting the connectable terminals of all the CT outlet terminal boxes to separate the secondary outlet wires from the CT body.

3. The indirect secondary through-flow method for the CT of the generator set according to claim 1, wherein the specific flow of the step 2) and the step 5) is as follows:

301) during the addition, fifty percent of the rated current of the secondary side of the CT transformer is added for the first time, and the rated value of the secondary side of the CT transformer is added after the measurement and the loop are ensured to be correct.

4. The indirect secondary through-flow method for the CT of the generator set according to claim 1, wherein the specific flow of the steps 4) and 8) is as follows:

401) the method comprises the steps that a pincerlike phase meter is used for measuring the actual output current value of a relay protection tester, the phase and the amplitude of an applied current can be accurately measured, the difference between a test value and the applied current is within an error permission range under normal conditions, if the difference is overlarge, a through-flow test needs to be stopped, the relay protection tester is closed, a secondary circuit is checked, and the problems that cables are broken or not, the connection of connectable terminals is unreliable and the like are mainly included;

402) some equipment such as a relay protection device can also read the polarity and the amplitude of the current, under the condition, the value measured by the equipment needs to be compared with the value measured by the pincerlike phase meter, if the difference between the two values is larger, one of the two equipment possibly has a problem, at the moment, the measured values of the two equipment are respectively checked with the added value, at the moment, the equipment possibly has a problem due to the larger difference, at the moment, the secondary through-flow test is stopped, and the experiment is carried out after the equipment is repaired.

5. The indirect secondary through-flow method for the CT of the generator set according to claim 1, wherein the specific flow of the step 10) is as follows:

501) after the test is finished, firstly, the power supply of the relay protection tester is turned off, then the current line connected with the relay protection tester and the added equipment is removed, the connectable terminal of the equipment is recovered, and finally the short-circuit wire of the CT outlet terminal box is removed and all the connectable terminals are recovered.

Technical Field

The invention relates to the technical field of power debugging and power testing, in particular to a CT indirect secondary through-flow method for a generator set.

Background

At present, China is still in the high-speed stage of economic development, although various industries face transformation at present, the demand of electric power as a unique secondary energy source which is efficient, flexible and large in China is still high, and various power plants are still built without stopping. For a power plant, measurement and acquisition of various electric quantity data of a unit are realized through CT and PT. For the CT, in daily production, many accidents occur because various problems exist in the secondary wiring of the CT, especially, the CT secondary circuit is opened to cause an extremely serious accident, which may destroy equipment, and may threaten the personal safety of the staff in the power plant. Therefore, in the debugging stage after the power plant infrastructure is finished, the CT secondary circuit inspection often becomes the central importance of the debugging work. The checking of the CT loop comprises a plurality of items such as secondary loop connection accuracy, CT polarity matching, accuracy level checking and the like, so that secondary loop wiring is frequently modified in the checking and debugging process, connection errors of the secondary loop, line damage and terminal virtual connection are possibly caused, a secondary through-flow test of a complete loop is carried out after the secondary loop is checked, the correctness and integrity of the secondary loop can be effectively detected, the open-circuit condition exists, and meanwhile, whether the current sampling value of each device connected with the CT secondary loop is accurate or not can be measured. However, the conventional secondary through-flow is usually measured by adding quantity at the terminal box of the unit CT body, the terminal box of the generator unit CT body is usually positioned at the neutral point and the terminal outlet of the generator, the field environment is complex, the operation difficulty is high, and the safety problem exists.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a CT indirect secondary current passing method for a generator set, the current passing adding position is selected to be carried out in an electric and electronic room with centralized current collecting equipment, better environment and convenient power supply of a current passing device, the current passing work of all electric equipment corresponding to a CT current secondary circuit can be completed through different connection modes only by a group of short wires at a CT terminal box, the time and the labor are saved, the condition that a tester is exposed to a complex field environment for a long time is avoided, and the work safety is improved.

In order to achieve the purpose, the invention adopts the technical scheme that:

a CT indirect secondary through-flow method of a generator set comprises the following steps:

1) carrying out preparation checking work before a unit CT secondary loop through-flow test, and entering the step 2 after all previous work preparation is finished);

2) turning on a relay protection tester power supply of a relay protection tester, adjusting the output of the relay protection tester power supply to be fifty percent of the rated current value, and entering step 3);

3) recording and collecting current values of all devices connected with the group of CT secondary circuits, and then entering the step 4);

4) checking whether errors between the secondary current display values and the measured values of the equipment and fifty percent of the sampling rated current of the equipment added by the relay protection tester are within an allowable range, generally, an equipment specification can determine error values of the current display of the equipment, if no special description exists, the error values are not more than +/-5%, if yes, the step 5) is carried out, and if not, the step 6) is carried out;

5) adjusting the relay protection tester to enable the output value of the relay protection tester to reach a rated value, and entering step 7);

6) closing the relay protection tester, checking the group of CT secondary circuits and connected equipment, and entering the step 2 after fault removal;

7) recording and acquiring current values of all devices of the set of CT secondary circuits, and then entering step 8);

8) judging whether the error between the measured CT secondary rated current value and the added CT secondary rated current value is in an allowable range, and generally, determining the error value of current display of each device by a device specification, if no special description exists, the error value of the current display should not exceed +/-5%, if yes, entering step 10), otherwise, entering step 9);

9) closing the relay protection tester, checking a secondary circuit and equipment, and entering a step 5 after defects are eliminated);

10) and finishing the CT secondary through-flow experiment.

The preparation and inspection work before the step 1) indirect CT secondary through-flow test comprises the following specific processes:

101) checking the integrity and correctness of the secondary loops corresponding to all the CTs in the group, wherein the integrity and correctness comprise whether the connection position of a cable and equipment is accurate, whether the connection at the interface of the secondary cable is firm and reliable, whether a terminal sliding sheet can be connected at the equipment is completely connected, and no looseness exists;

102) selecting any electric equipment connected with a set of CT secondary circuits as a dosing starting end of the relay protection tester, disconnecting the connection between the equipment and a connectable terminal of the set of CT secondary circuits (so that a dosing device needs to independently flow through a channel of the equipment after a test is finished to ensure that the sampling function of an equipment body is correct), then connecting a power supply of the relay protection tester, connecting the output end of the relay protection tester with a CT current return path side of a disconnection point of a current circuit of the electric equipment, preparing a set of short connecting wires in a CT outlet terminal box, connecting one side of the short connecting wires with the CT circuit dosed by the relay protection tester, and connecting the short connecting wires to the corresponding CT current outlet circuit when the CT secondary circuit of which equipment needs to flow through;

103) and disconnecting the connectable terminals of all the CT outlet terminal boxes to separate the secondary outlet wires from the CT body.

The specific processes of the step 2) and the step 5) are as follows:

301) during the addition, fifty percent of the rated current of the secondary side of the CT transformer is added for the first time, and the rated value of the secondary side of the CT transformer is added after the measurement and the loop are ensured to be correct.

The specific processes of the step 4) and the step 8) are as follows:

401) the method comprises the following steps of measuring an actual current output value of a relay protection tester by using a pincerlike phase meter, accurately measuring the phase and amplitude of an applied current, normally, if the difference between a test value and the applied current is within an error permission range, if the difference is overlarge, stopping a through-flow test, closing the relay protection tester, and checking a secondary circuit, wherein the problems of breakage of a cable, unreliable connection of connectable terminals and the like are mainly included;

402) some equipment such as a relay protection device can also read the polarity and the amplitude of the current, under the condition, the value measured by the equipment needs to be compared with the value measured by the pincerlike phase meter, if the difference between the two values is larger, one of the two equipment possibly has a problem, at the moment, the measured values of the two equipment are respectively checked with the added value, at the moment, the equipment possibly has a problem due to the larger difference, at the moment, the secondary through-flow test is stopped, and the experiment is carried out after the equipment is repaired.

The specific flow of the step 10) is as follows:

501) after the test is finished, firstly, the power supply of the relay protection tester is turned off, then the current line connected with the relay protection tester and the added equipment is removed, the connectable terminal of the equipment is recovered, and finally the short-circuit wire of the CT outlet terminal box is removed and all the connectable terminals are recovered.

The invention has the beneficial effects that:

the current adding place of the test is generally selected between electric and electronic rooms concentrated by electric equipment, the environment in the electronic rooms is safe, a relay protection tester power supply is easy to find, the tasks of measuring and adding can be even completed by one person, the time is greatly saved, meanwhile, the communication barrier caused by the original remote measurement of adding is eliminated, and the absolute consistency of the input value of the current and the theoretical measurement value is ensured.

The CT main body terminal box can indirectly complete the through-flow tests of all CT secondary circuits only by changing the wiring mode through a group of short wires, the operation is simple, an operator can temporarily leave the site only by changing the wiring mode of the wiring circuit according to the indication, the personnel safety is ensured, the time is saved, and the technical requirements on the site personnel are also reduced.

By means of the double comparison of the fifty percent current rated value and the hundred percent current rated value, the clamp meter and the measured value of the equipment, whether the equipment measurement is accurate or not can be accurately reflected, and the reliability of the electrical equipment is effectively checked.

The method is suitable for various generator sets and is convenient to popularize.

In conclusion, the CT secondary through-flow method saves time, is simple to operate, is safe and reliable, has strong practicability, can accurately check the CT secondary circuit and the equipment connected on the circuit, and is suitable for various generator sets.

Drawings

FIG. 1 is a flow chart of the S-shaped flow test of the present invention.

Fig. 2 is a schematic diagram of the principle of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples.

A CT indirect secondary through-flow method of a generator set comprises the following steps:

1) carrying out preparation checking work before a unit CT secondary loop through-flow test, and entering the step 2 after all previous work preparation is finished);

2) turning on a power supply of a relay protection tester (relay protection tester for short) device of the relay protection tester, adjusting fifty percent of the output rated current value of the relay protection tester, and entering step 3);

3) recording and collecting current values of all devices connected with the group of CT secondary circuits, and then entering the step 4);

4) checking whether errors between the secondary current display values and the measured values of the equipment and fifty percent of rated current applied by the relay protection tester are within an allowable range, and determining current display error values of the equipment by an equipment specification generally, if no special description exists, the error values are not more than +/-5%, if yes, entering a step 5), otherwise, entering a step 6);

5) adjusting the relay protection tester to enable the output value of the relay protection tester to reach a rated value, and entering step 7);

6) closing the relay protection tester, checking the group of CT secondary circuits and connected equipment, and entering the step 2 after fault removal;

7) recording and acquiring current values of all devices of the set of CT secondary circuits, and then entering step 8);

8) judging whether the error between the measured CT secondary rated current value and the added CT secondary rated current value is in an allowable range, and generally, determining the error value of current display of each device by a device specification, if no special description exists, the error value of the current display should not exceed +/-5%, if yes, entering step 10), otherwise, entering step 9);

9) closing the relay protection tester, checking a secondary circuit and equipment, and entering a step 5 after defects are eliminated);

10) and finishing the CT secondary through-flow experiment.

The preparation and inspection work before the step 1) indirect CT secondary through-flow test comprises the following specific processes:

101) checking the integrity and correctness of the secondary loops corresponding to all the CTs in the group, wherein the integrity and correctness comprise whether the connection position of a cable and equipment is accurate, whether the connection at the interface of the secondary cable is firm and reliable, whether a terminal sliding sheet can be connected at the equipment is completely connected, and no looseness exists;

102) selecting any electric equipment connected with a set of CT secondary circuits as a dosing starting end of the relay protection tester, disconnecting the connection between the equipment and a connectable terminal of the set of CT secondary circuits (so that a dosing device needs to independently flow through a channel of the equipment after a test is finished to ensure that the sampling function of an equipment body is correct), then connecting a power supply of the relay protection tester, connecting the output end of the relay protection tester with a CT current return path side of a disconnection point of a current circuit of the electric equipment, preparing a set of short connecting wires in a CT outlet terminal box, connecting one side of the short connecting wires with the CT circuit dosed by the relay protection tester, and connecting the short connecting wires to the corresponding CT current outlet circuit when the CT secondary circuit of which equipment needs to flow through;

103) and disconnecting the connectable terminals of all the CT outlet terminal boxes to separate the secondary outlet wires from the CT body.

The specific processes of the step 2) and the step 5) are as follows:

301) during the addition, fifty percent of the rated current of the secondary side of the CT transformer is added for the first time, and the rated value of the secondary side of the CT transformer is added after the measurement and the loop are ensured to be correct.

The specific processes of the step 4) and the step 8) are as follows:

401) the method comprises the steps that a pincerlike phase meter is used for measuring the actual output current value of a relay protection tester, the phase and the amplitude of an applied current can be accurately measured, the difference between a test value and the applied current is within an error permission range under normal conditions, if the difference is overlarge, a through-flow test needs to be stopped, the relay protection tester is closed, a secondary circuit is checked, and the problems that cables are broken or not, the connection of connectable terminals is unreliable and the like are mainly included;

402) some equipment such as a relay protection device can also read the polarity and the amplitude of the current, under the condition, the value measured by the equipment needs to be compared with the value measured by the pincerlike phase meter, if the difference between the two values is larger, one of the two equipment possibly has a problem, at the moment, the measured values of the two equipment are respectively checked with the added value, at the moment, the equipment possibly has a problem due to the larger difference, at the moment, the secondary through-flow test is stopped, and the experiment is carried out after the equipment is repaired.

The specific flow of the step 10) is as follows:

501) after the test is finished, firstly, the power supply of the relay protection tester is turned off, then the current line connected with the relay protection tester and the added equipment is removed, the connectable terminal of the equipment is recovered, and finally the short-circuit wire of the CT outlet terminal box is removed and all the connectable terminals are recovered.