Torsional vibration protection device easy to support waveform playback test

Abstract

The utility model discloses a torsional vibration protection device easy to support a waveform playback test, which is characterized in that the output ends of a rotating speed pulse speed measurement plug-in, a voltage and current measurement plug-in and a switching value input plug-in are all connected to a protection calculation plug-in, and the output end of the protection calculation plug-in is connected with a switching value output plug-in; the switching value output plug-in executes protection alarm or tripping according to the output of the protection calculation plug-in; the man-machine interface plug-in is used for man-machine interaction; the first conditioning signal measuring plug-in is used for measuring the rotating speed difference in a non-pulse form and sending the rotating speed difference to the protection calculation plug-in, and the second conditioning signal measuring plug-in is used for measuring the multi-path torsional vibration mode rotating speed in a non-pulse form and sending the rotating speed difference to the protection calculation plug-in. The change-over switch is used for connecting the first conditioning signal measuring plug-in or the second conditioning signal measuring plug-in to the protection calculation plug-in under the control of the protection calculation plug-in. The torsional vibration protection device can overcome the defects that in the prior art, two sets of external testers are needed for static testing of a TSR protection device, and a waveform playback detection mode is not supported.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of power plant main equipment relay protection, and relates to torsional vibration protection technology of large steam turbine generator unit and gas turbine generator unit, in particular to a torsional vibration protection device easy to support waveform playback test. BACKGROUND

[0002] The shaft system of a large steam turbine generator unit or a gas turbine generator unit is very long, up to tens of meters. Taking a large steam turbine generator unit as an example, the entire shaft system is usually composed of a high-pressure cylinder rotor (HP), a medium-pressure cylinder rotor (IP), two low-pressure cylinder rotors (LP1 and LP2), and a generator rotor (GEN). During normal operation, the rotors of the entire shaft system rotate synchronously, and can be regarded as a rigid body, and the angular displacement of the rotors in the rotating direction remains relatively fixed. When torsional vibration occurs, the rotors of the entire shaft system no longer rotate synchronously, and at this time, the entire shaft system is no longer regarded as a rigid body, but is approximated as a spring body of multiple mass blocks, the angular displacement of the rotors in the rotating direction is inconsistent, and the angular displacement relative to the synchronous rotation coordinate system oscillates in a certain pattern. Figure 1

[0003] Since the Mohave power plant in the United States experienced a torsional vibration accident in the 1970s, which caused damage to the shaft system of a steam turbine generator unit, the sub / super-synchronous oscillation of a power system and the torsional vibration of a unit have been fully researched. Both theoretical research and engineering practice have shown that sub / super-synchronous oscillation and unit torsional vibration may occur under certain conditions. The easy-to-occur mode of steam turbine generator unit torsional vibration is the "point-to-grid" form of a power plant for long-distance power transmission, and (1) there is a capacitor series compensation device on the outgoing line, or (2) the sending end is connected to a high-voltage direct current converter station, or (3) there is a large-scale new energy source in the surrounding area, etc. Severe torsional vibration can cause cracks in the weak links (mainly the shaft couplings and journal bearings) of the shaft system in a short time. Long-term torsional vibration with an amplitude that does not exceed the metal bearing capacity may also cause cracks in the weak links of the shaft system due to fatigue accumulation. In order to avoid the damage of torsional vibration to the unit, a torsional vibration protection device (also known as a torsional stress relay, English term: Torsional Stress Relay, abbreviated as TSR) needs to be installed for a steam turbine generator unit that has a risk of sub / super-synchronous oscillation and unit torsional vibration.

[0004] Regarding TSR protection, in the prior art at home and abroad, such as Figure 2 , a common method is to install a speed sensor on the support corresponding to the turbine main shaft toothed disc, and when the unit runs, the speed sensor outputs a speed pulse ω p The TSR protection device detects the speed pulse and calculates the current speed ω in real time. If the speed is stable without fluctuation, it is judged that there is no torsional vibration. If the speed fluctuates and a modal speed Δω corresponding to the natural torsional vibration mode frequency of the rotor shaft system occurs,​m If torsional vibration is detected, further investigation is conducted to determine whether the modal speeds diverge and whether the metal fatigue caused by the torsional vibration exceeds the limits (exceeding the alarm value or trip value), thereby achieving torsional vibration protection. Typically, TSR protection also requires measuring the generator's three-phase voltage u. abc Three-phase current i abc This allows us to determine the grid-connected operating status of the generator, enabling us to calculate not only the generator's active power (corresponding to electromagnetic torque) and accurately calculate the torque between two adjacent rotors in the turbine generator set's rotor shaft system, but also to observe the subsynchronous / supersynchronous oscillation components in the generator's three-phase current after torsional vibration occurs. Detailed technical solutions can be found in Chapter 11 of "Analysis and Control of Subsynchronous Resonance in Power Systems" (by Xie Xiaorong et al., Science Press, 2015).

[0005] The publicly disclosed patents involving TSR protection devices mainly include: "ZL200810057040.4 Steam Turbine Generator Shaft Torsional Vibration Protection Device", "ZL2015101995312.7 Steam Turbine Generator Shaft Torsional Vibration Protection Method and Protection Device", and "ZL201910877968.5 Steam Turbine Unit Instantaneous Transient Torque Protection Method and Device". All of these patents describe protection methods and devices. In particular, to identify torsional vibration, they all rely on detecting speed pulse signals and do not support non-pulse speed signals.

[0006] TSR protection devices require commissioning and testing before being put into operation; after a period of operation, they need to be inspected according to schedule. Figure 3 As shown, during static testing of the TSR protection device, a frequency-modulated pulse signal ω is output through a signal generator. p The pulse signal is supplied to the TSR protection device to simulate the turbine generator speed; the three-phase voltage u is output through the relay protection tester. abc Three-phase current i abc The TSR protection device is used to simulate the grid-connected operation of a generator. Because the signal generator cannot output multiple voltage and current signals suitable for the relay protection device, and the relay protection tester cannot output frequency-modulated pulse signals, static testing of the TSR protection device requires the simultaneous use of both a signal generator and a relay protection tester, necessitating a large number of external testers. Furthermore, the speed signal in dynamic simulation data or field-recorded waveform data is non-pulse. Although the simulation data and waveform data can be imported into the relay protection tester, the speed signal replayed is non-pulse, making it unsuitable for the TSR protection device. In other words, static testing of the TSR protection device cannot be performed using waveform playback. Utility Model Content

[0007] The utility model discloses a torsional vibration protection device easy to support waveform playback test can overcome the defect that TSR protection device static test needs two sets of external test appearance and does not support waveform playback detection mode in prior art.

[0008] In order to achieve the above object, the utility model discloses a solution is:

[0009] A torsional vibration protection device easy to support waveform playback test, including protection calculation insert, rotating speed pulse speed measurement insert, voltage current measurement insert, switching value input insert, switching value output insert, man -machine interface insert and working power supply, wherein working power supply provides working voltage for each insert, and the output end of rotating speed pulse speed measurement insert, voltage current measurement insert, switching value input insert is connected to protection calculation insert, and the output end of protection calculation insert is connected switching value output insert, and switching value output insert carries out protection alarm or tripping according to the output of protection calculation insert, and man -machine interface insert is used for man -machine interaction.

[0010] Still include first conditioning signal measurement insert, second conditioning signal measurement insert and change-over switch, wherein first conditioning signal measurement insert is used for measuring the rotating speed difference of non-pulse form and sending into protection calculation insert, and second conditioning signal measurement insert is used for measuring the multi-path torsional vibration mode rotating speed of non-pulse form and sending into protection calculation insert, and change-over switch is used for connecting first conditioning signal measurement insert or second conditioning signal measurement insert to protection calculation insert under the control of protection calculation insert.

[0011] The rotating speed pulse speed measurement insert is equipped with at least 4 acquisition ports, is used for collecting at least two paths for steam turbine generator head rotating speed and at least two paths for steam turbine generator tail rotating speed, and according to the rotating speed data collected, the rotating speed is sent into protection calculation insert.

[0012] The voltage current measurement insert is used for measuring generator end three-phase voltage, three-phase current, and sending into protection calculation insert.

[0013] The change-over switch adopts hardware switch or software switch.

[0014] After using the above scheme, compared with prior art, the utility model increases conditioning signal measurement insert SC, can adapt to measuring the rotating speed difference delta omega of non-pulse form and the multi-path torsional vibration mode rotating speed delta omega of non-pulse form. m1 ~ delta omega m5 Through change-over switch S and protection calculation control word K, the switching of the signal required by protection calculation is completed, and delta omega and delta omega m1 ~ delta omega m5The protection calculation does not need to depend on the rotational speed signal in the form of pulse, so that the static detection of the torsional vibration protection device only needs a set of external tester, and supports waveform playback detection, saves detection equipment, simplifies detection work, and improves detection efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Fig. 1 is a schematic diagram of a large steam turbine generator set shaft system; in the figure, HP is a high-pressure cylinder rotor, IP is a medium-pressure cylinder rotor, LP1 and LP2 are two low-pressure cylinder rotors, and GEN is a generator rotor;

[0016] Figure 2 Fig. 2 is an application scheme of a TSR protection device; in the figure, CT is a current transformer, PT is a voltage transformer, i abc is a generator terminal three-phase current (CT secondary value), u abc is a generator terminal three-phase voltage (PT secondary value), ω p is a rotational speed pulse;

[0017] Figure 3 Fig. 3 is a common method for static testing of an existing TSR protection device; in the figure, i abc is a generator terminal three-phase current (CT secondary value), u abc is a generator terminal three-phase voltage (PT secondary value), ω p is a rotational speed pulse;

[0018] Figure 4 Fig. 4 is a schematic diagram of a TSR protection device architecture of the utility model; in the figure, DSP is a protection calculation plug-in, PI is a rotational speed pulse speed measurement plug-in, AC is a generator voltage and current measurement plug-in, DI is a switch quantity input plug-in, DO is an alarm and tripping contact output plug-in, HMI is a human-machine interface plug-in, Pwr is a device working power supply, SC is a conditioning signal measurement plug-in, and S is a switching switch; i abc is a generator terminal three-phase current (CT secondary value), u abc is a generator terminal three-phase voltage (PT secondary value), ω p is a rotational speed pulse, and ω is a rotational speed; Δω is a rotational speed difference, Δω m1 ~ Δω m5 is a torsional vibration mode 1~mode 5 rotational speed;

[0019] Figure 5 Fig. 5 is a schematic diagram of TSR protection static testing of the utility model; in the figure, Δω is a rotational speed difference, Δω m1 ~ Δω m5 is a torsional vibration mode 1~mode 5 rotational speed, which is a non-pulse form signal output by a relay protection tester;

[0020] Figure 6is the waveform playback data used in the embodiment 2 of the utility model, and the rotational speed difference Δω' is the rotational speed difference of the first torsional mode;

[0021] Figure 7 is the waveform playback data used in the embodiment 3 of the utility model, and (a) is the rotational speed Δω' of the first torsional mode m1 , and (b) is the rotational speed Δω' of the second torsional mode m2 . DETAILED DESCRIPTION

[0022] The technical scheme and beneficial effects of the utility model will be described in detail below in combination with the drawings and specific embodiments.

[0023] Embodiment 1

[0024] As shown in Figure 4 , the utility model discloses a kind of easily support waveform playback test's torsional vibration protection device architecture schematic diagram. Torsional vibration protection device includes protection computing plug-in DSP, rotational speed pulse speed measurement plug-in PI, voltage and current measurement plug-in AC, switching value input plug-in DI, switching value output plug-in DO, man-machine interface plug-in HMI, working power supply Pwr, conditioning signal measurement plug-in SC, switching switch S;Wherein, working power supply Pwr gives each plug-in suitable working voltage, the signal output of rotational speed pulse speed measurement plug-in PI, voltage and current measurement plug-in AC, switching value input plug-in DI, conditioning signal measurement plug-in SC is given to protection computing plug-in DSP, after protection computing plug-in DSP completes protection calculation and logic discrimination, protection alarm or tripping is executed by switching value output plug-in DO, man-machine interface plug-in HMI is responsible for completing setting, viewing message, viewing recording, viewing analog quantity / state quantity, printing, man-machine interaction of reset.

[0025] The above-mentioned rotational speed pulse speed measurement plug-in PI supports not less than 4-way rotational speed pulse signal ω p , at least two-way is used for steam turbine generator head speed measurement, at least two-way is used for steam turbine generator tail speed measurement, and finally the rotational speed ω required for protection calculation is obtained.

[0026] The above-mentioned voltage and current measurement plug-in AC supports not less than 3-way voltage signal and not less than 3-way current signal, for measuring generator terminal three-phase voltage u abc , three-phase current i abc .

[0027] The above-mentioned conditioning signal measurement plug-in SC is divided into two, the first is used to measure the rotational speed difference Δω of non-pulse form, and the second is used to measure the rotational speed of multiple torsional modes in non-pulse form, including the rotational speed of the first torsional mode to the fifth mode, i.e. Δω m1 ~ Δω m5 ; Δω and Δω m1 ~ Δωm5 is an AC voltage signal outputted by the external tester through waveform playback; the plug-in SC internally comprises an attenuation circuit, an isolation circuit and a filter circuit, and converts the externally inputted AC voltage signal with an amplitude not exceeding 100V into an AC voltage signal with an amplitude not exceeding 10V which can be processed internally.

[0028] The above-mentioned switching switch S can be a hardware switch or a software switch, and the software switch is preferred; when the software switch is used, a control word S is set in the protection calculation, S=0 indicates that the non-pulse form of the speed difference Δω is used to do the protection calculation, and S=1 indicates that the non-pulse form of the torsional vibration mode 1~mode 5 speed Δω m1 ~Δω m5 is used to do the protection calculation; when the hardware switch is used, the switch position can be switched to the Δω channel or the Δω m1 ~Δω m5 channel.

[0029] The above-mentioned protection calculation plug-in DSP receives the signal outputted by the speed pulse speed measurement plug-in PI, the voltage and current measurement plug-in AC, the switching value input plug-in DI and the conditioning signal measurement plug-in SC, and a control word K is set in the protection calculation, K=0 indicates that the speed ω measured by PI is used to do the protection calculation, and K=1 indicates that the speed difference Δω or the torsional vibration mode speed Δω m1 ~Δω m5 measured by SC is used to do the protection calculation.

[0030] In this embodiment, the waveform playback method is used to do the torsional vibration protection device detection, and the method is as shown in Figure 5 The method imports the simulation data or the recording wave data into the external tester with the waveform playback function, and outputs the speed difference Δω or the torsional vibration mode speed Δω m1 ~Δω m5 to the SC plug-in of the torsional vibration protection device through the waveform playback simulation, and the control word K in the protection calculation is set to 1; at the same time, the external tester waveform playback simulation outputs the three-phase voltage u abc , the three-phase current i abc of the generator to the AC plug-in of the torsional vibration protection device; preferably, the external tester uses a relay protection tester.

[0031] Embodiment 2:

[0032] In this embodiment, the torsional vibration protection device is applied to a steam turbine generator set with the risk of subsynchronous oscillation and torsional vibration. The main parameters of the steam turbine generator are: rated capacity 667MVA, rated voltage 20kV, rated power factor 0.9, and rated speed 3000rpm.

[0033] In this embodiment, the same torsional vibration protection device as in Embodiment 1 is used, including a protection calculation module DSP, a speed pulse measurement module PI, a voltage and current measurement module AC, a switch input module DI, a switch output module DO, a human-machine interface module HMI, a working power supply Pwr, a conditioning signal measurement module SC, and a switching switch S; the functions of each module are the same as in Embodiment 1.

[0034] In this embodiment, the TSR protection device is detected using a non-pulse waveform playback method to detect the speed difference Δω. First, waveform data from a specific field test is acquired, including generator speed, generator three-phase voltage, and generator three-phase current. The speed difference Δω' is obtained by subtracting the synchronous speed of 3000 rpm from the speed data in the waveform data. Figure 6 As shown, Δω' exhibits a noticeable jump at the 2nd second; then as... Figure 5 As shown, the data is imported into the relay protection tester; then, by setting the waveform playback of the relay protection tester, a non-pulse speed difference signal Δω is output, which is an AC voltage signal; next, the speed difference signal Δω is input to the conditioning signal measurement plug-in SC of the TSR protection device. When the TSR protection device is tested, the switch S is a software switch, and setting S=0 indicates that the non-pulse speed difference Δω is used for protection calculation; at the same time, the control word K=1 for protection calculation settings indicates that the SC measurement is used for protection calculation.

[0035] In this embodiment, during waveform playback testing, to ensure that the speed difference used in the protection calculation matches the speed difference value in the recorded waveform data, the relay protection tester sets the transformation ratio of Δω' to Δω output to 20rpm / 40V. The SC plug-in includes an attenuation circuit, an isolation circuit, and a filtering circuit, converting the externally input Δω AC voltage signal into an AC voltage signal that the device can process internally. In this embodiment, 100V / 10V is used, meaning that when the externally input AC voltage signal is 100V, the internally processable AC voltage signal is 10V. Furthermore, the speed difference measurement stage after the SC plug-in of the TSR protection device is set to a transformation ratio of 4V / 20rpm. After this setting, when the speed difference Δω' in the waveform data reaches 20rpm, the output speed difference Δω voltage is 40V. After passing through the SC, it is converted into a 4V voltage signal that the protection device can process internally. After passing through the transformation ratio set in the speed difference measurement stage, the TSR protection device can measure the 20rpm speed difference, thus ensuring that the speed difference used in the protection calculation matches the speed difference value in the recorded waveform data. When playing back waveforms, the generator's three-phase voltage and three-phase current can be played back simultaneously, which is a standard function of the relay protection tester.

[0036] Example 3:

[0037] The torsional vibration protection device in the embodiment is applied to a steam turbine generator set with the risk of subsynchronous oscillation and torsional vibration. The main parameters of the steam turbine generator are as follows: rated capacity 667 MVA, rated voltage 20 kV, rated power factor 0.9, rated rotating speed 3000 rpm, the shaft system of the set includes a high-pressure cylinder rotor (HP), a medium-pressure cylinder rotor (IP), a low-pressure cylinder rotor (LP) and a generator rotor (GEN), the set has only one low-pressure cylinder rotor, and the shaft system parameters are as follows:

[0038] Table 1

[0039] Serial number Rotor moment of inertia (kg-m2) 2 )]]> 1 HP 1315.3 2 IP 5295.4 3 LP 32280 4 GEN 9859.7

[0040] The equivalent torsional stiffness between the rotors is as follows:

[0041] Table 2

[0042] Serial number Rotor Torsional stiffness (N-m / rad) 1 HP-IP 1.2649E8 2 IP-LP 1.4452E8 3 LP-GEN 1.5944E8

[0043] The natural modal frequency of the shaft system at the subsynchronous frequency is as follows: modal 1 frequency 21.40 Hz, modal 2 frequency 26.60 Hz.

[0044] In the embodiment, the same torsional vibration protection device as in Embodiment 1 is adopted, including a protection calculation plug-in DSP, a rotating speed pulse speed measurement plug-in PI, a voltage and current measurement plug-in AC, a switching value input plug-in DI, a switching value output plug-in DO, a human-computer interface plug-in HMI, a working power supply Pwr, a conditioning signal measurement plug-in SC and a switching switch S, and the functions of the plug-ins are the same as in Embodiment 1.

[0045] In the embodiment, the TSR protection device is detected by adopting the mode of playing back the torsional vibration modal rotating speed in a non-pulse form. Firstly, the recorded waveform data of a certain field is acquired, including the generator rotating speed torsional vibration modal 1 rotating speed Δω m1 and modal 2 rotating speed Δω m2 , generator three-phase voltage, generator three-phase current and other data, the two torsional vibration modal 1 and 2 rotating speeds are shown in Figure 7 (a) and (b), the torsional vibration occurs at the second moment, the two torsional vibration modal rotating speeds first increase in amplitude and then rapidly attenuate, and then the data is imported into a relay protection tester as shown in Figure 5 , the torsional vibration modal 1 rotating speed Δω m1 and modal 2 rotating speed Δω m2 are output in a non-pulse form by setting the waveform playback of the relay protection tester, at this time, Δω m1 and Δω m2 are alternating voltage signals, then Δω m1 and Δω m2The conditioning signal measurement plug-in SC is input to the TSR protection device. When the TSR protection device is detected, the switch S is a software switch, S=1 is set, indicating that the torsional vibration mode speed in a non-pulse form is used for protection calculation; at the same time, the control word K=1 set for protection calculation indicates that the SC measurement is used for protection calculation.

[0046] In the embodiment, when waveform playback detection is performed, in order to make the two mode speeds used for protection calculation the same as the two mode speed values in the recorded waveform data, the relay protection tester sets Δω m1 Convert Δω m1 The output variable ratio is (0.2 rad / s) / 20V, and Δω m2 Convert Δω m2 The output variable ratio is (0.2 rad / s) / 20V; the plug-in SC internally includes an attenuation circuit, an isolation circuit and a filter circuit, and Δω m1 and Δω m2 The alternating voltage signal is converted into an alternating voltage signal that can be processed internally, and in the embodiment, 100V / 10V is taken, that is, when the alternating voltage signal input externally is 100V, the alternating voltage signal that can be processed internally is 10V; further, the variable ratio 2V / (0.2 rad / s) is set for the two torsional vibration mode speed measurement links after the TSR protection device SC plug-in. After such setting, when the torsional vibration mode 1 speed Δω m1 reaches 0.2 rad / s, the output Δω m1 has a voltage of 20V, and after SC, it is converted into a 2V voltage signal that can be processed internally, and then, through the variable ratio set for the torsional vibration mode speed measurement link, the TSR protection device can measure the 0.2 rad / s torsional vibration mode 1 speed, and the torsional vibration mode 2 uses the same processing method, thereby ensuring that the two mode speeds used for protection calculation are the same as the two mode speed values in the recorded waveform data. When waveform playback is performed, the three-phase voltage and three-phase current of the generator can be played back simultaneously, which is a conventional function of the relay protection tester.

[0047] The above embodiments only illustrate the technical idea of the utility model, and cannot limit the protection scope of the utility model, and any modification made on the basis of the technical scheme according to the technical idea of the utility model falls within the protection scope of the utility model.

Claims

1. A torsional vibration protection device that easily supports waveform playback testing, characterized in that: It includes a protection calculation module, a speed pulse measurement module, a voltage and current measurement module, a digital input module, a digital output module, a human-machine interface module, and a power supply. The power supply provides operating voltage to each module. The outputs of the speed pulse measurement module, the voltage and current measurement module, and the digital input module are all connected to the protection calculation module. The output of the protection calculation module is connected to the digital output module. The digital output module executes protection alarms or trips based on the output of the protection calculation module. The human-machine interface module is used for human-machine interaction. It also includes a first conditioning signal measurement plug-in, a second conditioning signal measurement plug-in, and a switching switch. The first conditioning signal measurement plug-in is used to measure the non-pulse form of speed difference and send it to the protection calculation plug-in. The second conditioning signal measurement plug-in is used to measure the non-pulse form of multi-channel torsional vibration mode speed and send it to the protection calculation plug-in. The switching switch is used to connect the first conditioning signal measurement plug-in or the second conditioning signal measurement plug-in to the protection calculation plug-in under the control of the protection calculation plug-in.

2. The torsional vibration protection device that easily supports waveform playback testing as described in claim 1, characterized in that: The speed pulse measurement plug-in is equipped with at least 4 acquisition ports, which are used to acquire at least two channels for the turbine generator head speed and at least two channels for the turbine generator tail speed, and the speed is obtained based on the acquired speed data and sent to the protection calculation plug-in.

3. The torsional vibration protection device as described in claim 1, which easily supports waveform playback testing, is characterized in that: The voltage and current measurement module is used to measure the three-phase voltage and three-phase current at the generator terminals and send them to the protection calculation module.

4. The torsional vibration protection device that easily supports waveform playback testing as described in claim 1, characterized in that: The switching switch can be a hardware switch or a software switch.

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